When crossing gray (A) female Drosophila flies with normal wings (B) with black (a), short-winged (b) males in the offspring, there were not only gray flies with normal wings and black with short wings, but also a certain number of individuals with gray body and shortened wings, as well as a black body and normal wings. Determine the genotypes of parents and offspring if it is known that dominant and recessive traits are paired. Make a crossover pattern and explain the results.
The scheme for solving the problem includes:
1) parental genotypes:
Female AaBv. Gametes AB and ab; male – aabb. Gametes – ab;
2) offspring genotypes: AaBb – gray body, normal wings, aabb – black body, short wings, Aavb – gray body, short wings, aaBb – black body, normal wings;
3) the appearance of four phenotypic groups is due to crossing over during the formation of germ cells in the female and the formation of additional gametes — Ab and aB.
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