Crossed the diheterozygous male Drosophila flies with a gray body and normal wings (dominant characters) with females with a black body and shortened wings (recessive characters). Make a scheme for solving the problem. Determine the parental genotypes, as well as the possible genotypes and phenotypes of F1 offspring, if the dominant and recessive genes of these traits are pairwise linked, and crossing-over does not occur during the formation of germ cells. Explain the results.
1) parental genotypes: (M) aabb (gametes: ab), (O) Aabb (gametes: AB, ab);
2) offspring genotypes: 1 AaBb – gray body normal wings and 1 aabb – black body shortened wings;
3) since the genes are linked, but crossing over does not occur, the male gives two types of gametes AB and ab, and the female gives one type of gametes ab. In the offspring, only two phenotypes appear in the ratio 1: 1. (other genetic symbols are allowed that do not distort the meaning of the solution to the problem)
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.