Parent child identification refers to the identification of whether the accused parents and children are related to each other according to the genetic laws of genetic traits between their offspring and parents by using the theories and technologies of biology, genetics and related disciplines.The cases involved include: disputes over the upbringing of children born out of wedlock, disputes over property inheritance, the identification of the birth of a newborn due to the wrong transfer of the hospital delivery room, and the claim of abducted and separated children.Parent child identification is mainly based on the genetic law of human blood type and simple genetic traits other than blood type. Genetic traits are controlled by genes located on chromosomes in the nucleus, and individual characteristics are passed on to offspring through gene transmission between parents and offspring.The transmission of genes follows certain rules.(1) The genes of offspring come from their parents, half from their father and half from their mother.(2) Unless one parent (or both parents) has a gene, the offspring will not have the gene.(3) If one of the parents is homozygous, all the offspring carry the gene.The most commonly used method in paternity testing is blood group testLeukocyte blood group, serotype and erythrocyte enzyme type)mendelian inheritance Those passed from parents to offspring can be used as the basis for paternity testing.However, the results of blood group identification can only be used as the basis for denying the paternity, althoughNon parent exclusion rateThe probability of affirming paternity can reach more than 99%, but it is still not 100% sure.Identification of genetic traits other than blood type, such as fingerprint, earwax type, PTC taste blindness, appearance characteristics, duration of pregnancy, fertility and sexual intercourse ability, can only be used as reference for parent-child identification.Modern biotechnologyThe development of has been able to obtain DNA fingerprints by hybridization of DNA fragments. This technology can reduce the probability of random similarity to one in 30 billion when applied to paternity testing.[1]
Paternity test is a typical application of genetic statistics theory in forensic medicine.The parent-child identification is based on the genotyping information (such as STR loci) of genetic markers of parents and offspringLikelihood ratio testThinking is a way to speculate whether there is a kinship between father and child.The statistical indicators commonly used for paternity testing are the paternity index andAverage non parent exclusion rate。In the paternity test report, these two indicators are generally reported at the same time, so as to comprehensively evaluate the test results[2]。
Identification reasons
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The main reason for paternity testing: with the development of science and technology, and the change of traditional family concept, the level and demand of modern biotechnology coincide.Due to the liberalization and people's openness to gender relations, ethical contempt, life style and other changes, many couples are worried that their children are not their own after marriage. Most of them are husbands who suspect that the children are not their own, and there are women who have had sexual relations with more than one person before pregnancy. In order to find out who the child's biological father is, they put forward an identification when they are pregnant.
Judicial paternity test
InheritanceThe dispute shall be determined whether it is natural;
Identification of rapist;
Claiming abducted and trafficked children;
Unmarried first child settlement, over birth settlement, unable to provide birth certificate;
The victims (air crash, tsunami, etc.) cannot be identified;
Custody disputes.
Individual paternity test
Suspect that the child is not born;
It is suspected that the hospital delivery room or nursery will replace the newborn;
The separated family members recognize their relatives;
The paternity test also includes:Genetic identification(paternal or maternal), immigration identification, etc.
According to the different purposes of identification, paternity identification can be divided into judicial identification andindividual appraisement。
1. Individual paternity testThe appraisal client has the right not to provide any documents because it is not open.Samples can be taken by themselves and sent to professional appraisal institutions, and the appraisal results are only provided to the appraisal client.The appraisal results can be used as evidence in civil proceedings.
2. Judicial paternity testIt is completely open, and the consent of the client's father, mother and child must be verified, and the client must be present face to face with all relevant valid documents, including ID card and household register.Appraisal resultsIt can be used for judicial purposes (registration, immigration, litigation, etc.), or as evidence in court.
1) Judicial expertise can only be applied to litigation activitiesIt is a scientific appraisal activity initiated by the judge in the process of specific litigation and trial procedure.In other words, those who do not participate in litigation activities, that is, they do not have to do judicial paternity tests if they do not litigate in the court;The appraisal initiated by the court after the lawsuit is brought to the court is called judicial appraisal.
2) Forensic expertise activities must follow the procedural law and relevant judicial interpretations, and expert conclusions that violate procedures cannot become expert materials.
Judicial paternity test is a kind of test that needs to be provided to courts, public security organs, notary offices, entry-exit management offices and other judicial institutions. The judicial paternity test report has legal effect and can be used as evidence.
The judicial paternity test report of the center is applicable to mainland China, Hong Kong, Macao, Taiwan and other countries and regions (except for some countries and regions due to political system restrictions), and can be used for litigation, overseas notarization, visa processing, household registration, etc.
Judicial authentication should be: the subject of authentication is legal, the authentication materials are legal, the authentication procedures are legal, the authentication steps are legal, and the authentication methods and standards are legal.The judicial authentication must be issued by the relevant institutions (public security organs, people's procuratorates, people's courts) with a power of attorney. The authentication completed through a series of judicial notarization procedures is called judicial authentication, and is only used as court evidence. The authentication conclusion must be subject to court cross examination before it is effective.
Characteristics of judicial paternity test:
The acceptance procedure of judicial paternity test is relatively rigorous to ensure the accuracy, authenticity, fairness and effectiveness of the test results.
(1) The appraised person must come to the Center in person to handle real name entrustment;
(2) The appraised person must provide his true and valid identity certificate;
(3) The appraised person must promise that the information provided is true and effective;
(4) Our appraisal center carefully checks the identity information of the appraised person and takes photos on site;
(5) Parent child identification samples must be collected by the staff of the Center, and notaries must be present when necessary.
3) More than 80% of the paternity tests have not started the judicial appraisal, which belongs to personal appraisal.
Personal identification is a biological identification of an individual's genetic genes by an identification institution. In the sampling process, there is no need for the public security organ to issue a power of attorney, nor for the applicant to provide identity cards and other certificates and consent forms. It is only a voucher for the paternity identification of the appraiser and can be used as one of the evidences, but the identification process and accuracy of the identification results are consistent with the judicial identification.
Individual identification
It is generally used in criminal cases to identify whether DNA information belongs to the same person[2]。
Affinity identification
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Genetic theory has confirmed that half of the children's genomic DNA comes from their biological parents.The kinship identification carried out by the forensic material evidence profession includes the following categories:
1. Routine paternity identification: This is the type of paternity identification with the largest demand, including paternity identification of three parents and children (also known as triplets), and paternity identification of both parents and children (or both parents and children) (also known as triplets).The accuracy of such identification can reach 99.999999%.
2. Identification of intergenerational kinship: This type of identification refers to the identification of the kinship between great grandparents and great grandchildren (great granddaughters), and between grandparents and grandchildren (granddaughters).It also includes simple paternal kinship identification, such as to confirm the kinship between great grandfather and great grandson, grandfather and grandson, and simple maternal kinship identification, such as to confirm the kinship between great grandmother and great granddaughter, grandmother and granddaughter.
3. Difficult kinship identification: In addition to the above two categories, there are some more difficult kinship identification, such as the identification of siblings (brothers, siblings, siblings, sisters) and cousins whose parents suspect (have no), the identification of kinship between uncles and nephews, aunts and nieces, and the identification of kinship between uncles and nieces (nieces).
Identification principle
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The theoretical basis for determining paternity is Mendelian segregation law.According to this rule, during the formation of gametocytes, pairs of alleles separate from each other and enter their respective gametocytes.Sperm and egg cells are fertilized to form offspring, and the child's two genomes come from the mother and the father;Therefore, the same pair of alleles is one from the mother and one from the father.If the identification result conforms to this rule, the paternity relationship will not be excluded; if not, the paternity relationship will be excluded (except for variation).In most cases, the relationship between mother and child is known, and it is required to identify whether the hypothetical father and child are biological.At this time, first, from the comparison of maternal and paternal genotypes, it can be determined that the gene in the child's gene may be from the father (paternal gene, OG). Then observe the genotype of the hypothetical father. If there is no paternal gene, the paternal relationship between the hypothetical father and the child can be excluded.If it is assumed that the father also has the paternal gene, the result cannot exclude the paternal relationship of the assumed father. If the mother in a case is FGA-22/23 and the child is 22/25, it can be determined from the comparison that the paternal gene is FGA-25.In this case, it is assumed that the parent 1 is FGA-22/24 type;Assume that the parent 2 is type 24/25.It is assumed that Father 1 does not have the biological father gene 25, so the biological relationship between him and the child can be excluded;In contrast, if Father 2 has FGA-25, it is not ruled out that he has a biological relationship with the child.
Qualification steps
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The operation steps of DNA paternity test are as follows:
Step 1: DNA extraction
The DNA contained in the nucleus of the sample is extracted, and then purified to remove impurities in the sample.
Step 2: PCR amplification
The Chinese name of PCR ispolymerase chain reaction In a nutshell, PCR amplification is to replicate the fragments we need through enzymatic reaction on a PCR instrument to the extent that they can be seen through some special instruments.
Step 3: Post PCR reaction
This step is mainly the preparation stage of ABI sequencer detection. Open the double stranded DNA and add some internal standards for detection, mainly to mark the length of the detected segment.
Step 4: Capillary sequencer detection
Because DNA is charged, the electrophoresis speed of different DNA segments is different through capillary electrophoresis. Under the same voltage and electrophoresis time, the swimming distance is different. These different lengths and distances can be distinguished through the internal standard measurement added earlier, and can be displayed on the computer through certain software, which is convenient for the detection personnel to process and analyze data.
Step 5: Analyze the data and issue a report
It is mainly that the inspectors analyze, summarize and calculate the results obtained, and then draw appraisal conclusions and reports.
Qualification application
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Criminal cases
1. If rape leads to pregnancy, the criminal suspect should be identified;
2. An unnamed corpse or skeleton that is highly corrupt and needs to be identified;
3. Parent child identification of abducted and trafficked children;
4. In case of death in a traffic accident, relatives need to claim the corpse and have to pay compensation.
Civil cases
1. Handling immigration;
2. Household registration of children;
3. Property inheritance disputes;
4. Suspect that the baby is replaced;
5. Identification of blood relationship of extra children;
6. Identification of blood relationship of children born out of wedlock;
7. Identification of blood relationship of separated children;
8. The man wanted to confirm whether the child was born;
9. The adopted child seeks his or her own parents;
10. Help find the lost family members;
11. Help women to obtain child support expenses from the father of the child;
12. Help parents obtain custody and visitation rights of their own children;
13. The blood relationship identification of test tube babies, to identify whether the test tube babies obtained through in vitro fertilization have laboratory errors;
The family registration paternity test is a very serious matter. It is also a paternity test derived from China's unique household registration management system. It is widely used in the field of paternity test. The 2010 census, due to the preferential measures for family registration, set off a paternity test fever.
1、 In the following cases, parent-child identification is required before registration:
1. No birth certificate.For various reasons, the child was not born in a hospital with obstetrics and gynecology qualifications, or was not born in a hospital, so there is no standardized birth certificate, and parent-child identification is required when registering.Or there is a birth certificate, but the name of the parents on the birth certificate is inconsistent with the name on the ID card and the household registration book, and a parent-child identification certificate is required.
2. Because the child was abducted and lost, and then recovered through various ways, the household registration needs to be together with the biological parents, and the paternity test report is required.
3. If the child is born out of wedlock, the existing legal documents cannot prove the biological parental relationship of the child.Or for single parent families, the child's household registration needs to be transferred from the father's side to the mother's side, or from the mother's side to the father's side, and parent-child identification needs to be done.
4. Abandoned children go home to settle down.If the child is adopted and needs to be adopted back, or because of avoiding family planning, the child's household registration needs to be transferred to the name of his or her own parents, and parent-child identification needs to be done.
5. According to the special regulations of the department, some departments need parents and children of the industry to prove their parent-child relationship when they recruit workers and employees, because they are afraid of other industries entering special industries.For example, the recruitment of Zhengzhou railway system requires parent-child identification certificate.
6. When an adopted child goes into the household, it is necessary to prove that the child is not related to the adoptive parents.
2、 Procedures required for the family registration paternity test: the family registration paternity test belongs to the process of self adducing evidence by the family registration related person, so the identification certificate only needs to be provided by the identification party:
1. Certificates that can prove the identity of the appraised person: such as ID card, household register, military identity certificate, birth certificate, etc.Those who do not have the above certificates need the people's government at or above the township level, the neighborhood office, and the police station to apply for authentication certificates.
2. The appraised person must go to the judicial appraisal center to take blood to participate in the appraisal and complete the identity verification.It is mainly used to verify identity certificates, leave fingerprints and take photos.
3. If it is inconvenient for the appraiser to go to the Judicial Expertise Center for sampling due to the inconvenience, the appraiser can contact the staff of the Judicial Expertise Center for on-site sampling and identity verification.
3、 Select the accreditation body.There are many institutions to do paternity testing, but the household paternity testing belongs to the scope of judicial expertise. Therefore, to select an identification institution, you must have a Judicial Expertise License. The paternity testing report must be valid nationwide and recognized by public security, judicial and other departments nationwide,If necessary, an internationally recognized judicial appraisal institution is also required to make an appraisal (for example, a child is abducted to a foreign country or Hong Kong or other regions).
4、 Personnel involved in the identification of family registration paternity test: only considering the needs of family registration, they can be identified as father son (daughter) or mother son (daughter) by the identification conclusion.But due to the paternity testGene mutationConsidering the factors and many factors of registered permanent residence, it is better to do the paternity test for three parents and children (women).
5、 The identified person has transfused other people's blood within half a year, or conducted bone marrow transplantation within two years, and can not draw accurate conclusions.The appraiser should avoid the above time[1]。
Handling process
Families who need to do paternity testing need to make an appointment by telephone, bring all their valid identity documents, fill in the judicial entrustment formalities in the identification institution, record their fingerprints, take photos and sign, and then the staff of the identification institution will collect blood stain test materials for the parties.[3]
Development history
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In 1984, British geneticistAlec Jeffries(Sir Alec John Jeffreys) invented DNA identification technology.[4][9-11]
In 1986, British geneticist Alec Jeffries will developDNA fingerprintTechnology was first used in criminal investigation.[5-6]
The first DNA database in the world was established by the British Court Science Service (FSS). Experimental research began in 1990, but it was not until 1995 that the authoritative and complete national DNA database was completed with the improvement of relevant laws.[7]
The research on DNA identification in China began in 1987 and has been applied to the actual case determination in 1989.[7-8]
In 1991, the first paternity test took place in China. The Ministry of Public Security first used the "DNA fingerprint test", which was limited to criminal technical identification at that time, to determine whether a father and son were related by blood.[11-14]
After 2000, the first generation of "DNA fingerprint" technology was gradually replaced by "fluorescent multi locus STR multiplex amplification detection technology (referred to as STR technology)".[11]
Single nucleotide polymorphism (SNP) is considered as the third generation genetic marker.[15]The third generation "DNA identification" technology "SNP" has been applied, which can detect more trace DNA, which means that the new technology can detect biological evidence with more serious damage.[11][16]
Original method
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Appearance contrast
Because of heredity, there are some similarities in the appearance and skin color between father and son, mother and son, brothers and sisters. It is probably the most original method to determine the parent-child relationship through the comparison of appearance, but this method is just a guess, judgment, as a reference.
Bone dripping test
The method of bone dropping is to drop the blood of the living on the bones of the dead. If the blood can penetrate into the bones, it can be concluded that the living has a blood relationship with the dead, otherwise it will not.Three KingdomsWu kingdomThe Kuaiji Sage Biography written by Xie Cheng recorded the case of claiming the elder brother's bones from the bones of his brother's blood drop;(The Southern History · The Comprehensive Biography of the King of Yuzhang also records the case that the blood drop of the son was used to test the kinship on the father's bone; until the Song Dynasty, it was famousForensic medicineScientistSong CiRevenues from bone dropping experience《A catalogue of vindication》Medium.From a modern point of view, this method is not scientific, but it pioneered the use of blood groups to identify blood source relationships.
Blood test
The blood drop test method, also known as the combined blood test method, is to put the child's blood together with the adult's blood. If it can be combined, it is the parents' own, otherwise it is not.This recognitionSample methodOnce in the Song Dynasty of ChinaForensic medicineIt was recorded in the book.There is no scientific basis for this method. The blood of parent-child relationship may not be fused, but the blood of non parent-child relationship may be fused.
Modern methods
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Blood group test
blood typeTesting for parent-child identification is to confirm the parent-child relationship through the inspection and comparison of blood types.According to the recognition at the end of the 19th centuryMendel's law of heredityPeople realize that human blood type is based on hereditygeneIt is passed on to the next generation, so children born to parents with a certain blood type also have corresponding blood types, which lays the foundation for blood type identification of parent-child relationship.
Used for blood group test to identify parent-child relationshipBlood group systemMainly:
The more blood type systems tested, the higher the accuracy. If the results of blood type tests indicate that there is no genetic relationship, the conclusion of denying parent-child relationship can be made, but if there is genetic relationship in the results, it can not be completely determined that it is parent-child relationship.
In the 1970s, it was found that paternity test could be carried out with the antigenicity of white blood cells, with an accuracy of 80%.Combined with blood type test, it can achieve a high degree of accuracy.
Chromosome polymorphism
In the 1980s, medical scientists pioneered the use ofchromosomePolymorphism technology for identifying parent-child relationship,Chromosome polymorphismAlso known as heteromorphism, it refers to the small variation of various chromosome shapes commonly seen in the normal population (such as: body enlargement, duplication or absence, fluorescence intensity variation of specific particle area, etc.), which can be inherited.This technology uses its shape to identify parent-child relationship, which depends on the subjective judgment of technicians, and its accuracy is not satisfactory.
DNA identification
DNA typing is the most widely used method to identify parent-child relationship.Human blood, hair, saliva, oral cells and bones can all be used for paternity testing, which is very convenient.
A person has 23 pairs (46) of chromosomes. A pair of genes at the same position of the same pair of chromosomes is called an allele. Generally, one is from the father and the other is from the mother.If the allele of a certain DNA site is detected, one is the same as the mother, and the other should be the same as the father, otherwise there will be doubt.
Using DNA for parent-child identification, only a dozen to dozens of DNA sites are tested. If all are the same, parent-child relationship can be determined. If more than three sites are different, parent-child relationship can be excluded. If one or two sites are different, consideration should be given toGene mutationIt is possible to do some additional site detection to identify.The accuracy rate of DNA paternity test is nearly 100% for denying parent-child relationship, and 99.99% for affirming parent-child relationship.
DNA paternity testing is mainly determined by the following characteristics
Somatic cell stability: The DNA of the blood, saliva, semen and organs of the same individual is consistent, and it is permanent for the same healthy person, which is the most basic premise.
Individual high specificity: the difference in genetic essence at the molecular level of DNA of different individuals determines that the same restriction enzyme digests genomic DNA, and the number and length of allele fragments of one individual and another cannot be the same, thus producing individual specific DNA.
Pressmendelian inheritance Heredity: Through a large number of family investigations, it has been proved that all allelic bands in the offspring DNA can be found in the parents' DNA, and the transmission of fragments conforms to Mendelian inheritance law.
Paternity index
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The ratio between the probability that the father provides the paternity gene to become the father of the child and the probability that the random man provides the paternity gene to become the father of the child is called the paternity index (PI). The former possibility is assumed to be X;The latter possibility is assumed to be Y.In the above example, it is assumed that the paternal 2 genotype is 24/25 heterozygote, and the possibility that he provides the paternal gene FGA-25 is 1/2, that is, X=1/2.The chance for random men to provide FGA-25 is the frequency of this gene, that is, Y=0.0958.Therefore, the PI value of this example is 0.5/0.0958=5.22.If it is assumed that Father 2 is indeed the biological father of the child, no matter how many loci are detected, the biological relationship between him and the child will not be excluded. In all detected loci, each locus can calculate a PI value. The cumulative PI value of multiple loci is equal to the product of the PI values of each locus, but the premise is that there is no genetic linkage between the detected loci.
The triad genotype combination can be summarized into three principles:
(1) When the father is assumed to be homozygous, X=1; when the father is assumed to be heterozygous, X=1/2; but when the heterozygote assumes that both genes of the father may be biological father genes, X=1.
(2) When only one biological father gene is involved, the Y value is equal to the frequency of the biological father gene.
(3) If two biological father genes are involved, the Y value is the sum of the two biological father gene frequencies.
common problem
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1. What is DNA paternity testing?
DNA（Deoxyribonucleic acid）It is the atomic material of cells in the human body. Each atom has 46 chromosomes. In addition, male sperm cells and female eggs have 23 chromosomes each. When sperm and eggs combine, these 46 atomic chromosomes create a life. Therefore, each inherits half of the molecular material from the biological father, and the other half is obtained from the biological mother.
DNA paternity test is very different from traditional blood test. It can be tested on different samples, including blood, cheek cells,HistiocyteSamples and semen samples.Because blood types, such as type A, type B, type O or type RH, are more common in the population, they are not as effective as DNA paternity tests to identify everyone.Except for realHorse hoovesBesides, everyone's DNA isthe one and onlyOf.Because it is so unique, likefingerprintSimilarly, DNA is the most effective method for paternity testing.
2. How accurate is DNA paternity test?
DNA paternity test is one of the most accurate paternity tests.If the DNA patterns of children and test men are in one or moreDNA probeIf it does not match, then the tested man will be 100% excluded, that is, he is 0% and may be the biological father, but he cannot be the biological father of the child.
If the DNA pattern of the mother, child and the tested father is completely consistent, then 99.97% or more probability can be calculated. This result proves that he is actually the biological father of the child.Most American courts accept the probability of 90% as evidence of paternity.
3. Does the child need to reach a certain age to accept DNA paternity test?
The DNA paternity test is age free. The traditional blood type test requires children to be at least 6 months old.Also, a large number of blood samples are required, usually more than two teaspoons.It is difficult to apply this method to children.On the contrary, DNA paternity test only requires a few drops of blood (about 1/4 or 1/2 teaspoon), or cheek cells obtained by oral wiping. This kind of test uses a small amount of blood or oral testing, so that DNA testing can even be carried out on newborn babies or children.Because DNA is formed in the binding period, the test can even use (Chorionic villi Sampling/CVS) placental hormone or extractamniotic fluid(amniocentesis) method.
The paternity test can be conducted on the samples collected by the funeral home workers of the deceased.When a person has died or disappeared, he or she can rearrange his or her DNA organization on his or her blood relatives.
4. Can paternity testing be conducted without mother's participation?
sure.DNA paternity testing is very effective, even in the absence of the mother is still effective.If the mother participates or does not participate, and the DNA organization arrangement of the child and the tested man does not match, the tested person will be 100% excluded as the biological father.If the tissue arrangement matches, then we can calculate 99.95% or more of the probability of birth father.If an individual takes a minor child for the test, he/she shall carry the identity document and sign a form about his/her legal right to take a child for the test.
5. Are oral (cheek) smears accurate?
Another alternative to testing blood is a sample collection method called buccal swab. Since DNA exists in every cell in the body, the accuracy of the test results obtained by using the samples collected by the smear method is the same as that of blood samples.
When collecting samples, use a cotton swab to gently smear in the mouth of the child, and DNA can be extracted from the mouth. This procedure is not mandatory and painless, and is most suitable for children. Because this method is used to extract DNA, more steps can be taken, and blood can be taken from adults while samples can be obtained from children by oral swabbing. Adults can also choose to use oral swabbing test.
6. Is it OK for the tested people to be distributed in different cities?
No problem at all.
7. Can we do DNA paternity test only with hospital certificate or lawyer's letter?
not always.
8. Can paternity testing be done before a child is born?
sure.With DNA identification, the parent-child test can be performed before the birth of the child. The DNA test can pass CVB placental hormone, usually 10 to 13 weeks after pregnancy, or 14 to 24 weeks after pregnancy by amniotic fluid extraction.Any kind of operation shall be performed by an OB/GYN doctor.
9. Principles and procedures of DNA paternity test
DNA is extracted from several drops of blood, gill cells or cultured tissue fibers.Cut the DNA sample into small segments with domain elements, put them into gel, push the small pieces of DNA with electrophoresis tank to separate them, put the separated genes on nylon film, use special DNA probes to find genes, the same genes will be condensed into one, and then use special dyes to display the black bar code condensed into one by DNA probes under the X-ray environment,The barcode visible to the naked eye of children is very special - half is identical with the mother, and half is identical with the father.This process is repeated several times. Each probe is used to find different parts of DNA and form a unique bar code. With several groups of different probes, more than 99.95% paternal probability or resolution can be obtained.
10. Could you please explain the results of the paternity test
The child will have a stripe that is the same as the biological mother and another bar code that is the same as the AF1 of the father to be confirmed. This person is the biological father;The excluded man (AF2) does not have the same barcode as the child.
Affirming paternity: the probability of paternity is greater than 99.99% or greater (legally proved to be the biological father)
Denial of paternity: three or more gene loci do not conform to the genetic law (100% excluded as biological father)
Due to the large population base in China, it is generally recommended to use more than 20 STR loci to draw correct conclusions.
Sample collection
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1、 Blood stain sample collection method：
1. Prepare in advance before blood collectionAlcohol cotton ball, blood collection needle, medical disinfection gauze, paper envelope.
2. When taking blood, first sterilize the blood taking part with alcohol cotton ball, and then sterilize the blood taking needle. Take five drops of blood, big and small, from the thumb cover, and drop them on the medical gauze.
3. The blood of adults and children is dropped on different gauzes, and marks (such as parents and children) are made to record the collection date.
matters needing attention:
1. Blood stains can be taken from ear edge blood or fingertip blood, and infants can collect heel blood.
2. The bloodstains should be dried in the shade on the table, and should not be heated or exposed to the sun.
3. The blood samples of different people shall not contact each other, and shall be put into different kraft paper envelopes, which shall be clearly marked.
2、 Nail collection method
Sampling method:
1. Before sample collection, the person who provides the sample shall first remove the dirt in each nail (toothpick, etc. can be used), then wash his hands with clean water and dry them with disposable tissue or gauze;
2. The sampling personnel shall also wash their hands and wear gloves before sampling;
3. Use nail clippers or scissors (clean with water or alcohol before each use to avoid residual DNA substances of the former) to remove the free edge of the nail, and then put it on the white paper prepared in advance;
4. When cutting nails, the closer to the inside (close to the finger flesh), the better. After cutting, wrap them with clean white paper (do not use plastic bags to seal them). At least 3 nails are required.
matters needing attention:
1. When collecting samples, the fingernails cannot be directly touched by the skin of people other than the provided samples;
2. After natural drying in the shade, put it into a paper envelope. Please do not use plastic film or plastic bag to package it, so as to avoid mildew affecting the test quality;
3. After the sample is extracted, it should be mailed to the identification agency as soon as possible. If it needs to be stored, it should be stored in a dry, low temperature and dark place.
3、 Collection methods and requirements of cigarette ends
1. Collect 2-3 cigarette butts (after removing the ash) that the appraiser has smoked;
2. After collection, put cigarette butts into paper envelope bags (plastic bags are not allowed to be used for sealing), and mark them.
matters needing attention:
1. Confirm that the cigarette butts collected were smoked by the same appraiser;
2. Try to avoid touching the smoking part of cigarette butts when collecting samples;
3. Please send (mail) the samples to the identification center as soon as possible after extraction to avoid DNA degradation due to environmental factors and affecting the test results.
4、 Amniotic fluid sample extraction
Special reminder!amniotic fluidThe sample must be taken from a regular hospital of Grade III or above with the advice and help of an experienced registered obstetrician and gynecologist.To ensure the safety of pregnant women and fetuses.The number of samples during pregnancy depends on the doctor's diagnosis of your physical condition.
Fetal amniotic fluid paternity test generally requires 3-6 ml amniotic fluid samples.The samples must be identified as soon as possible, especially in summer, it is best to send them in ice bags.
5、 Oral sampling
DNA collection is very simple, painless, safe and hygienic, and can be completed in one minute.
Note: Avoid touching the oral swab with your hands.All testers should rinse their mouths with clean water first. When children drink milk, please take oral samples after an hour;
Basic sanitary conditions for collecting samples: clean hands, new oral swabs (single headed swabs sold in pharmacies), clean envelopes.
1. First, mark the clean paper envelope with the sample collection date, sample identity, such as father, mother, child, and name or code.
2. Put a cotton swab into the child's mouth, gently scrape both sides of the mouth (inner cheek, cheek) and sublingual area with the cotton swab head, gently rotate or scrape it for about 10 times, and then take it out. Repeat to take 3-5 pieces.
Note: Please do not touch the cotton ball part of the oral swab with your hand during the collection process. Please rotate and brush slightly to ensure that sufficient DNA is obtained.
After collection, it can be directly packaged with breathable paper envelopes (breathable envelopes will naturally dry in the shade).(Plastic bags cannot be used because airtight will cause the sample to become moldy or smelly, degrade DNA, and affect the experiment, unless some special samples need to be stored in the refrigerator, and daily samples can be packed in breathable envelopes)
Note: Please do not mistake the sample. Please ensure that the sample is consistent with the person marked on the packaging envelope.
Precautions for oral swab samples:
Avoid touching the cotton swab head with your hands. Rinse your mouth with clean water before collecting.The samples collected by the above methods can be stored in a dry environment for 2-3 months.
The oral swab should be dried in the shade and put into a paper envelope to prevent the oral swab from mildewing and affecting the detection.
The oral swabs of different people need to be stored separately and identified.
Advantages of oral test sample collection method: painless and convenient.
6、 Hair collection
Precautions: Avoid touching the hair follicle of the sample with hands!
First, mark the clean envelope with the date of sample collection and the identity of the sample, such as the name of father and child.
Remove at least 5 hairs from the hair, eyelashes, armpits, etc. (hair follicles can be seen clearly with the naked eye at the end of the hair).
Note: Do not touch the hair follicle with your hands during the collection process, and make sure that you can see the clear hair follicle with the naked eye at the end of the hair.
Put the hair just pulled out into the marked envelope immediately.It is necessary to check whether there are clearly visible hair follicles in the hair.
Advantages of hair sampling method: it is the simplest sampling method without time and place restrictions, and has high concealment.The accuracy of paternity test using hair is completely consistent with the sampling methods such as blood sampling.
Note: Please do not touch the hair follicle with your hands.Please do not load samples that fall on the ground or have been pulled out for a long time.Please do not mistake the sample. Please ensure that the sample is consistent with the identity of the person marked on the plastic bag.
Identification method
1. Blood group identification.Blood group identification is the determination of paternity according to the genetic law of blood group.ABO typeBlood group heredityA, B and OAlleleControlled.Everyone has any two of these genes, and these two genes can be the same.When two chromosomes are paired, six genes can be combined, namely AAAO、BB、BO、AB、OO，These six genes are the genetic basis that determines the individual characteristics of organisms, called genotype.Relative to this, the actual human character is calledphenotypeThis is commonly referred to as blood type.The paternity relationship is determined according to the genetic law of blood type.All blood type systems are based onmendelian inheritance From one's parents toProgenyCan be used as the basis for paternity test.
2. Comparison of physiognomy features, that is, according to the similarity of special signs such as face type, height, ears, nose, eyes, etc., as an auxiliary and reference for blood group testing.
In addition, there are also methods such as skin texture inspection, genetic diseases, earwax disease, taste blindness, inferring pregnancy period, birth period and determining reproductive capacity.The above methods must be comprehensively used in paternity test, in which blood group test is the main method.Modern biotechnologyThe development of DNA can also obtain DNA by hybridizationfingerprintThis technology can reduce the random similarity rate to 1/30 billion when applied to paternity testing.The paternity test can generally draw three conclusions: negating parent-child relationship, affirming parent-child relationship, or neither affirming nor denying parent-child relationship.
Today's science and technology have greatly improved the accuracy of paternity testing, using DNAGene identification technologyAfter that, the accuracy of affirming biological paternity was more than 99.99%, and the accuracy of denying biological paternity was 100% excluded.With the progress of technology, the samples examined can be identified from pure blood in the past to hair, saliva, bones, body fluids, etc. Even unborn fetuses can be identified by maternal amniotic fluid.
Blood group heredity
Special tips:The relationship between blood type and heredity is generally lifelong.
Human blood types are generally divided into A, B, O and AB.Blood type is inherited by means of chromosomes in cells.There are 23 pairs of chromosomes in human cells. Each pair of chromosomes is composed of two single chromosomes, one from the father and the other from the mother.The main components of chromosomes are those that determine genetic traits and functionsDeoxyribonucleic acidDNA is what people often call DNA.DNA can be divided into many segments, each of which has a specific genetic trait and function. These segments are calledgene。a pairchromosomeA small segment of DNA at the same position on two single chromosomes inAllele。
ABOBlood group systemThe gene locus of is on chromosome 9.HumanABO blood groupControlled by three genes A, B and O, but eachHuman cellsThere are only two ABO system genes on the ninth pair of chromosomes in, that is, an allele of AO, AA, BO, BB, AB, OO, in which A and B genes areDominant geneO group is a recessive gene.ABO blood group systemHereditary law can be used as a reference when the gene is not mutated, but blood type alone cannot be used to judge the blood source relationship.
Strictly speaking, the blood type locus is only one of many genetic loci, which certainly has certain reference value.However, because the routine blood group identification is known by naked eye observation under relatively simple conditions, there is a large error. Moreover, blood type only represents one site, which is more rigorous than the DNA paternity identification, which is often more than a dozen or dozens of sites.
ABO blood group identificationThe principle of RBC is to divide blood groups into four types: type A, type B, type AB and type O according to the presence or absence of A antigen or/and B antigen on red blood cells.AvailableRBC agglutination testABO blood type can be accurately identified by positive (serum test) and negative (cell test) typing.The so-called positive typing is to use known anti A and anti B typing serum to determine whether there is corresponding A antigen or/and B antigen on the red blood cells, and the so-called reverse typing is to use known A cells and B cells to determine whether there is corresponding anti A or anti B in the serum.
Parent: type A+type A, possible offspring: type A, type O, impossible offspring: type B, type AB
Parent: type B+type A, possible offspring: type A, type B, type AB, type O, impossible offspring: none
Parent: type B+type B, possible offspring: type B, type O, impossible offspring: type A, type AB
Parent: one or both of them are AB type, and the offspring may be A, B, AB type, but the offspring cannot be O type
Parent: type A+type O, possible offspring: type A, type O, impossible offspring: type B, type AB
Parent: type B+type O, possible offspring: type B, type O, impossible offspring: type A, type AB
Parent: type O+type O, possible offspring: type O (no variation, 100% type O), impossible offspring: type A, type B, type AB
notes:blood typeIdentification cannot be used as the standard for determining whether there is a genetic relationship. Only DNA paternity test is the gold standard for determining whether there is a genetic relationship.
Common sense of appraisal
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What is the difference between legal use appraisal and personal appraisal?
The identification method and accuracy rate of legal use identification and private identification are identical.The only difference is that the legal use identification requires the subject to provide fingerprints, photos, and identity certificates, and the sample sampling process needs to be conducted by legal witnesses.Private identification does not need to provide photos or fingerprints. The whole sampling process can be carried out by yourself and is completely confidential.Therefore, the results of DNA identification of samples collected without authorization have no legal effect.
Can paternity test be conducted without the participation of biological mother?
The birth mother can choose not to participate in the identification.In the paternity test, the samples of the child and the hypothetical father are usually enough to know the results, and the mother can choose not to participate in the test.The biological mother is also tested, and the conclusion is more accurate.Because the child's genes come from the mother and the father.If there is a biological mother as a reference (i.e. parental identification), the genes of the birth father can be clearly deduced according to the genotype of the mother and the child, so as to compare with the disputed father (i.e. you).If there is no mother, the father's gene will be derived directly from the child's gene. There are many possible cases, and the final statistical value deviation is relatively large.
In fact, the results of 15 STR loci commonly used by us have been used for computer simulation of single parent cases. For two unrelated people, with this detection system, there are at least three violations of genetic laws. 99.99% of non fathers can be excluded, but 1/1000 may be wrongly identified because they cannot be excluded.Therefore, the difference between our single parent identification and other institutions is that we also add a kit and nine detection indicators, which is more accurate and avoids deviation as much as possible.This is also the reason why the fee for single parent identification is higher than that of the birth mother.
Does the paternity test need to be attended?
The paternity test can be divided into two types, one is to have judicial effect, such as litigation, immigration, household registration, etc;The other is just to understand the results, not involving judicial purposes.For the former, it is necessary to provide the identity certificate of the party concerned. The parents can provide the identity card, and the children can provide the birth certificate or household register to prove their identity (to prove that the client is the child's guardian).If they have entered the judicial process or have hired a lawyer, they can be entrusted by the judge or lawyer to conduct appraisal.It can also be entrusted jointly or unilaterally by both parties.For the second type, it is unnecessary to provide any information, but it can be anonymous and can bring its own samples.The two types of fees, identification methods, and identification standards are identical, but there is a difference in the procedure, that is, a legally effective judicial identification certificate. We need to review the identity cards of the parties and take photos.
Is it harmful to pregnant women and fetuses to do fetal paternity test?
The forensic doctor of the identification center said that there is no need to worry, because this technology is very mature, whether it is to take villi or amniotic fluid samples, it is the same as prenatal diagnosis of the fetus, and basically will not cause any harm.The fetal paternity test is carried out by extracting villus or amniotic fluid from pregnant women. To ensure safety, it is recommended that pregnant women choose a Grade III A obstetrics and gynecology hospital.The relevant technologies of the tertiary level obstetrics and gynecology hospital are mature and will not harm the fetus and pregnant women.
The identification center has a special car to pick up and send and staff to accompany customers in the fetal paternity test. Amniotic fluid extraction is also carried out by professional doctors in the third class under B-ultrasound, which is safe and reliable.In addition, the identification center has accepted tens of thousands of cases of national fetal (prenatal) identification entrustment, and has rich identification experience.
What circumstances need to do immigration paternity test?
1. If one of the parents of the child is of a nationality other than China, and the child was born in China, the household registration relationship needs to be transferred abroad.
2. Both parents of the child are foreign nationalities. The child was born in China, and the child settled abroad with their parents.
3. People of foreign nationality who have direct relatives in China need to settle abroad.
4. Other situations such as Chinese nationals settling abroad, children moving with them, etc.
Fetal identification
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Fetal paternity test, refers to the use of genetic technology to identify the father of the fetus in the genetic sense.When it is not known who the father of the fetus is“Prenatal paternity test”Cells can be extracted from amniotic fluid of pregnant women, and paternity can be confirmed by identifying fetal DNA (deoxyribonucleic acid).For paternity testing, fetal DNA can be detected through villus biopsy and amniotic fluid identification from the fetal stage.After 10 weeks of pregnancy, you can do a villus puncture test, and after 16 weeks of pregnancy, you can do an amniotic fluid test.This article introduces the method of fetal paternity test.
1. The leucorrhea of pregnant women should be highly clean, which is 1 degree.
2. Pregnant women should not have inflammation such as cold, sore throat and fever.
3. The blood routine examination showed that the white blood cells were not high.
IIAmniotic fluid identification
1. Pregnant women should not have inflammation such as cold, sore throat and fever.
2. The blood routine examination showed that the white blood cells were not high.
Warm tips for pregnant women and fetus identification：
1. Pregnant women need to take a rest before the operation. If they have a cold, sore throat and fever, they cannot accept the operation.
2. Breakfast can be eaten on the day of the hospital examination, without fasting blood drawing.
3. Before the pregnant woman who has taken the villus biopsy comes, she needs to have a B-scan.Determine the pregnancy period, do a leucorrhea inspection, and the operation can be performed if the cleanliness is normal.
4. Pregnant women should not take a bath on the day after surgery and should not have sex for half a month.
5. Wear more clothes to avoid colds.
It is understood that paternity testing can be divided intoSingle parent identificationandParental identificationAmong them, single parent identification is the most common, that is, one of the husband and wife takes their children for identification without telling the other party, and all children are falsely called "physical examination".According to the head of the Judicial Expertise Institute, more than 70% of the paternity examiners are men. They suspect that their partners are unfaithful and secretly bring their children for identification in order to understand."The child does not look like me", "The child was born at the wrong time" and so on are all reasons why these men suspect that the child is not born.
On the one hand, the rapid growth of the number of paternity tests shows that society is making progress and people are willing to solve problems through scientific means.On the other hand, it also shows that there is a growing lack of trust and understanding between couples and lovers.I suggest that you should be careful about the paternity test and have enough resultsPsychological enduranceSo as not to cause harm to the spouse and children.
Face the results correctly
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When we plan to do a paternity test, our mental state is the most important.
In most people's eyes, the most intuitive aspect of paternity testing is to test whether the spouse (or wife, to be exact) is loyal.Men are not afraid of hardship, fatigue or even bloodshed.But, Dai“Green hat”It is the most taboo and shameful thing for men.
The husband suspected that his wife had a "third party", and even coaxed and tricked him into taking his children to have a "physical examination", but secretly did a paternity test;Young girls, in order to become rich, deliberately make themselves "accidentally" pregnant, and use parent-child testing as a threat, especially willing to be "mistresses"... Since when, parent-child testing seems to have become a "patent" for digging "third parties" and "big money".
"In fact, this is a misunderstanding. The parent-child identification has extraordinary social significance in finding relatives and bodies in disasters (such as the earthquake), finding abducted children, and helping raped women find evidence for suspects." For example, if a woman who has been raped previously wants to find evidence, she must wait until the child is born, which is undoubtedly an unbearable pain for the female victims,Through fetal DNAappraisalYou can find the biological "father".
As judicial expertise, paternity testing is used to provide objective, scientific and neutral material evidence.The emergence of paternity testing technology should be the progress of society. As a new scientific means, it is actually paternity testing. Its original purpose is to reflect the right to know, so as to solve the crisis of trust in the family and resolve conflicts, rather than becoming the "killer" of emotional loyalty.The reason why paternity testing has become a sensitive social topic is that it involves the problem of men "wearing green hats".Using paternity test, modern people can easily determine the blood relationship between relatives. However, this "convenience" also brings more challenges to modern people's marriage relationship.I called myself "Dad" for many years, and suddenly told myself very seriously: "I am not your father, because you are not my own child...".The family had a very harmonious life, but suddenly a report came that they were not "one family" at all, and their life would change from then on.
On the other hand, DNA paternity testing is becoming more and more popular, and is more and more known and accepted by most people. Many people choose to verify directly through technical means rather than obsessing about it, which should be regarded as a social progress;In modern society, everyone's survival, life and work are under great pressure. If you can use a simple and direct method to confirm your heart or remove your doubts, it is better than depression.
There were not so many people to do identification before. The first reason was that the technology was immature and the application field was limited. For example, the original DNA paternity testing technology could only be used for criminal cases and could not be used for civil paternity testing. Moreover, the identification cost was high and the technical requirements were not always high at that time;A father who has doubts about parent-child relationship has no way to prove his doubts.
China is a country that values consanguinity and blood inheritance. The father's doubt about whether the child is his own will be confirmed by scientific means and will continue.
Procedures required for immigrant paternity test:
1. When applying for immigration paternity test, the identified person shall provide the certificate that can prove his identity (such as ID card, household register, birth certificate, etc., only one is required);
2. Some countries need to be entrusted by the notary office for visa. If required, the notary office should provide the authentication certificate of the power of attorney.
Migrant parentage identification process:
1. The appraised person signs the power of attorney for judicial appraisal and collects samples in the appraisal center. If he cannot go to the appraisal center in person, he can also collect samples by himself for mailing.
2. The collected samples will be sent to the laboratory for DNA testing, and the identified can wait for the identification report.
3. The appraisal center will generally issue an appraisal report within 5 working days.
It is suggested that the identified person should communicate with the customer service staff of the identification center in advance when conducting the immigration paternity test. The customer service staff will help the identified person with professional knowledge in the first time to solve the doubts and problems encountered in the identification process.
