In cattle, hornlessness (hornlessness) and black coat color dominate over horniness and red color. The genes for both traits are not linked
In cattle, hornlessness (hornlessness) and black coat color dominate over horniness and red color. The genes for both traits are not linked and are located on different chromosomes. When crossing a hornless black bull with a hornless, but red cow (for several years), the calves turned out to be all black, but one of them was horned. Determine the likely genotypes of the parents and offspring.
Given:
A – gene for hornlessness (hornlessness)
a – horniness gene
B – gene for black color
b – gene for red color
R: polished, red x polished, black
F1: hornless, black; horned, black
Define:
probable genotypes of F1 parents and offspring
Crossing scheme
R: ♀ Aabb x ♂ AaBB
hornless hornless
red black
G: Ab, ab AB, aB
F1: ¾ (75%) polished, black: AABb: 2AaBb
¼ (25%) horned, black: aaBb
Answer:
probable genotypes of P parents:
♀ Aabb x ♂ AaBB
hornless hornless
red black
probable genotypes of F1 offspring:
¾ (75%) hornless, black: ААВb: 2АаВb
¼ (25%) horned, black: aaBb
