In the Ayrshire breed of dairy cattle, mahogany- and- white color is dependent u
ID: 187608 • Letter: I
Question
In the Ayrshire breed of dairy cattle, mahogany- and- white color is dependent upon a gene, Cm, that is dominant in males and recessive in females. It’s allele for red- and - white (Cr) acts as dominant in females but recessive in males A) what is the mode of inheritance B) if a red-white bull is crossed to a mahogany- and - white heifer, what phenotypic and genotypic frequencies are expected in F1 and F2? C) if a mahogany- and- white cow has a red- and white calf, what sex is the calf? D) what genotype is not possible for the sire of the calf in part (c)? In the Ayrshire breed of dairy cattle, mahogany- and- white color is dependent upon a gene, Cm, that is dominant in males and recessive in females. It’s allele for red- and - white (Cr) acts as dominant in females but recessive in males A) what is the mode of inheritance B) if a red-white bull is crossed to a mahogany- and - white heifer, what phenotypic and genotypic frequencies are expected in F1 and F2? C) if a mahogany- and- white cow has a red- and white calf, what sex is the calf? D) what genotype is not possible for the sire of the calf in part (c)? A) what is the mode of inheritance B) if a red-white bull is crossed to a mahogany- and - white heifer, what phenotypic and genotypic frequencies are expected in F1 and F2? C) if a mahogany- and- white cow has a red- and white calf, what sex is the calf? D) what genotype is not possible for the sire of the calf in part (c)?Explanation / Answer
Answer A) This is "Sex-influenced mode of inheritance" because we see that the same allele is dominant in one sex and recessive in another. such type of inheritance pattern is influenced but not limited to the sex.
Answer B) As per the given data, Mahgony-white(Cm) is dominant in males and recessive in females, it means that the genotype for Mahgony-white males would be Cm_ and genotype for Mahgony-white females would be CmCm. similarly, Red-white(Cr) is dominant in females and recessive in males, it means that the genotype for Red-white females would be Cr_ and genotype for red-white males would be CrCr.
So the parental crosses would be P1 x P2, where P1 = red-white bull = CrCr and P2 = mahogany-white heifer = CmCm
so F1 would be CmCr and F2 would be CmCm, CmCr and CrCr.
so, the genotypic ratio would be F1= Mahogany-white males (CmCr): Red-white females (CrCr) in 1:1 ratio.
in the F2 generation, F1 x F1 or CrCm x CrCm
F2 = CrCr : CrCm : CmCm as All red-white : males Mahgony-white, females red-white : All mahgony-white.
Answer C) If a Mahgony-white cow has a red-white calf.it means Mahgony-white cow = CmCm and the red-white calf = CrCm. it would a female as red-white is dominant in females.