When two lines of silkworm were crossed, the caterpillars of which produce white cocoons, in the first generation F1 all cocoons were yellow
When two lines of silkworm were crossed, the caterpillars of which produce white cocoons, in the first generation F1 all cocoons were yellow. During subsequent crossing of hybrids in the second generation, splitting occurred: 9 yellow cocoons and 7 white ones. Determine: 1) the nature of inheritance of the cocoon color trait; 2) genotypes of parents and offspring F1 and F2.
1) Cocoon coloration is inherited according to the type of complementary gene interaction (or recessive epistasis);
2) if the genes that control the color of the cocoon are designated as A and B, then:
a) genotypes P: (women) AAbb, (husband) aaBB;
b) genotypes F1: AaBb;
c) genotypes F2: AABB: AABb: Aabb: AaBB: AaBb: Aabb: aaBB: aaBb: aabb in the ratio 1: 2: 1: 2: 4: 2: 1: 2: 1.
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