In most chicken breeds (plymouthrock, wyandot), the C gene determines the colored plumage, and its allele c – white. The Leghorn breed has an epistatic gene I, which suppresses the development of pigment even in the presence of gene C. Its allele – gene i – allows gene C to exert its effect. Leghorn chickens with genotype IICC have white plumage due to epistasis of gene I over gene C; Wyandota chickens with the iicc genotype have white plumage due to the absence of the dominant pigmentation allele – C.
1) White Leghorn chickens with the IICC genotype are crossed with chickens of the White Wyandot breed (Dog). Determine the splitting of the F1 and F2 hybrids.
2) Crossed diheterozygous white Leghorn with pigmented Wyandotte. Half of the chicks are white and half are colored plumage. Determine the genotype of the Wyandot chicken.
3) Chickens crossed diheterozygous white leghorn with pigmented wyandot. Among the chickens, a cleavage was found in a ratio of 5 whites: 3 pigmented. Determine the Wyandotte genotype.
4) Two white individuals were crossed: a diheterozygous white leghorn with a white wyandot. What is the probability of dyed chicks appearing in F1?
1) In F1 100% unpainted, in F2 13 (unpainted): 3 (painted);
2) the genotype of the Wyandot IICC chicken;
3) Wyandotte genotype iiCc;
4) the probability of occurrence of colored chickens in F1 is 25%.
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