Topic content:
Among the following groups of traits, those belonging to relative traits are
A. High stems and green pods of peas
B. Sheep's black hair and rabbit's white hair
C. Fine and long lint of cotton
D. Double eyelid and single eyelid
Best answer:
D
Answer analysis:
There is no explanation for this question
Test core:
Biological characteristics:
1. Biological characteristics: physiological characteristics, morphological characteristics and behavioral characteristics.
2. Character type:
(1) Relative character: Different performance types of the same character of an organism.
(2) Character separation: dominant and recessive characters appear simultaneously in hybrid offspring. For example, in the DD × dd cross experiment, the dominant characters (DD and Dd) and recessive characters (dd) appeared in the F2 generation formed after self crossing of hybrid F1 generation.
(3) Dominant trait: the trait shown by F1 in DD × dd cross test; For example, the F1 generation pea in the textbook shows a high stem, that is, a high stem is dominant. Dominant genetic factors (genes) determine dominant traits, which are represented by capital letters. For example, high stems are represented by D.
(4) Recessive traits: traits not shown by F1 in DD × dd cross test; For example, F1 generation pea does not show dwarf stem in the textbook, that is, dwarf stem is recessive. It is the recessive gene that determines the recessive character, which is represented by lowercase letters, for example, dwarf stem is represented by d. Allele: A gene that controls a relative trait.
(5) Dominant relativity: when parents with the same traits cross, hybrid seeds do not show recessiveness in the first generation, showing the intermediate traits of both (incomplete dominance) or colleagues showing the traits of two parents (co dominance).