In canaries, the sex-linked gene B determines the green color of the plumage, b – brown. The presence of a tuft depends on the autosomal
In canaries, the sex-linked gene B determines the green color of the plumage, b – brown. The presence of a tuft depends on the autosomal gene C, its absence depends on c.
1) A green crested male is crossed with a brown female without a tuft. Determine what offspring can be expected: a) in F1; b) from backcrossing F1 hybrids with maternal and paternal forms.
2) From crossing a green male without a crested with a brown crested female in the offspring, a splitting was obtained: 1 male brown crested, 1 brown without a crested and 2 green crested females. Determine the genotypes of the parents.
3) From crossing green crested birds, a green crested male and a brown without a crested female were obtained. Determine the genotypes of the parents.
1) a) From the crossing of a homozygous green crested male with a brown female without a crested in F1, green crested females (CcXBY) and green crested males (CcXBXb) in a ratio of 1: 1 can be expected; b) from backcrossing F1 hybrids with the maternal form, green crested females and green crested males can be expected in a 1: 1 ratio (genotypes CCXBY, CcXBY, CCXBXB, CcXVXB in a 1: 1: 1: 1 ratio); from backcrossing F1 hybrids with the paternal form, one can expect green crested females, green females without a crest, brown crested females, brown females without a crest, green crested males, green males without a crest, brown crested males, brown males without a crest in a 1: 1 ratio : 1: 1: 1: 1: 1: 1 (genotypes CcXBY, ccXBY, CcXbY, ccXbY, CcXBXb, ccXBXb, CcXbXb, ccXbXb in a ratio of 1: 1: 1: 1: 1: 1: 1: 1);
2) genotypes P: (female) CcXbY, (male) ccXBXb;
3) genotypes P: (female) CcXBY, (male) CcXBXb.
