In sheep, horniness of A dominates over hornlessness (hornlessness) a, gray color of wool B – over black b. When black sheep are crossed with each other, only black lambs are born, gray and black – half gray lambs, half black, when crossing two gray – gray and black, and there are two times more gray than black. Determine: 1) what are the features of inheritance of wool color in sheep; 2) what offspring can be expected from crossing sheep with the genotype (women) AaBb x (husband) aabb; 3) what offspring and in what numerical ratio can be expected from crossing two diheterozygous sheep.
1) A dominant gene in a homozygous state causes the death of organisms;
2) from crossing sheep with the genotype (wives) AaBb, (husband) aabb, you can get gray horned, gray horned, black horned and black horned offspring in a ratio of 1: 1: 1: 1 (genotypes AaBb, Aabb, aaBb, aabb in a ratio of 1: 1: 1: 1);
3) from crossing two diheterozygous sheep, you can get horned gray, horned black, hornless gray and hornless black offspring in a ratio of 6: 3: 2: 1 (genotypes 2AABb: 1Aabb: 4AaBb: 2Aabb: 2aaBb: 1aabb).
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