synonymDNA hybridization(DNA molecule with complementary base sequence) generally refers to DNA molecular hybridization
DNAMolecular hybridization is based onComplementary baseSequentialDNA molecule, can be accessed viaBase pairHydrogen bond is formed between them to form stableDouble chainZone.Before DNA molecular hybridization, the DNA molecules of the two organisms should be extracted from the cells, and then heated or pH raised toDouble stranded DNAMolecules are separated into single chains. This process is calleddenaturation。Then, put the DNA single strand of two organisms together for hybridization, and use the DNA single strand of one organism in advanceisotopeMark.If there are complementary parts between two biological DNA molecules, a double stranded region can be formed.Due to the high sensitivity of isotope detection, even if one millionth of a double stranded region is formed between two biological DNA molecules, it can also be detected.
taxonomyOf different speciesDNA moleculeCan be carried out betweenMolecular hybridizationHowever, DNA molecules of distant speciesHybrid moleculeIs much less likely than that of related species.For example, bacteria andEukaryotic cellThe possibility of hybridization between DNA molecules is very small;When DNA molecules of different bacteria hybridize, some complementary fragments can be formed;Human DNA molecule andmiceOnly a small amount of human DNA single strand and mouse DNA single strand can form hybrid molecules when crossing between DNA molecules ofBase pairing。However, the formation of DNA hybrid molecules between humans and mice is easier than that between humans and yeast.stayBiological evolutionDuring the process, the base sequence in DNA also changed.The higher the degree of complementarity between DNA single strands of two organisms, the higher the degree of formation of double helix segments through molecular hybridizationgenetic relationshipThe closer;On the contrary, the farther the kinship is.Therefore, we can use DNA molecular hybridization technology to identify the genetic relationship between species.
Molecular hybridization technology
Announce
edit
Complementarynucleotide sequenceThrough Walson CrickBase pairingForm stable heterozygosityDouble chainmoleculeDNA moleculeThe process of hybridization is called hybridization.The hybridization process is highly specific, and specific target sequence can be detected according to the known sequence of the probe used.
hybridizationThe two sides are the probe used and the nucleic acid to be detected.The test object can be clonedGenomic DNA, or total cell DNA or totalRNA。The nucleic acid detected according to the method used can be purified or hybridized in cells, that is, cell in situ hybridization.The probe must be labeled for tracing and detection.Use the most common probeMarkersyesisotopeHowever, due to the safety of isotopes, manynon-isotope labelingProbe method.
molecular hybridization of nucleic acidIt has high sensitivity and high specificity, so this technology canmolecular biologyIt has been widely used in the field of screening cloned genesrestriction map ProductiongenomeQualitative and quantitative detection of specific gene sequences and diagnosis of diseases.Therefore, it is not only widely used in the field of molecular biology, but alsoclinical diagnosisThe number of applications on is also increasing.
Figuratively
Announce
edit
Let me give you a metaphor. I hope it will help you understand.Host DNA (there are many host DNA for cloning) is compared to many unlocked "doors", and you want to insert (or replace a segment of sequence) into host DNATarget geneIt can be compared to a specific "lock", and thisGene probeIt is the "key" that can open the lock.If you can use the "key" to open a "door", it means that the "lock" has been installed.That is to say, if the hybridization signal can be detected, the target gene has been connected to the host DNA.
Principle of hybridization
Announce
edit
As for how to see whether hybridization is possible, this is to mark the probe (there are many kinds of marks, biological, fluorescentradioactivityAfter hybridization, it is necessary to elute, and only this specific hybridization can be retained, and then check the markers on the probe to see whether it is hybridized.For example, the "key" above is like trying with a string of "keys", but you can first make a mark on the "key" you want. You don't need to know the teeth of the "key" (the teeth here can be imagined as the sequence of probes), just know the mark on the "key".
