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What is the probability of a gamete from an individual with the ZZ-ZW sex determination system, having two pairs of autosomes and a pair of sex chromosomes, Z and W, with the genotype alleles A and b on chromosome Z?

User Fadid
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Final answer:

The probability of a gamete from an individual with the ZZ-ZW sex determination system having the genotype alleles A and b on chromosome Z is 50 per cent for A and 50 per cent for b, since the individual is heterozygous for these alleles. All gametes from this individual will carry a Z chromosome because the individual is homozygous ZZ.

Step-by-step explanation:

The question is asking about the probability of a gamete from an individual with a ZZ-ZW sex determination system, with two pairs of autosomes and a pair of sex chromosomes (Z and W), and genotype alleles A and b on chromosome Z. In birds, which use the ZZ-ZW system, a homogametic male has two Z chromosomes (ZZ), while the heterogametic female has one Z and one W chromosome (ZW). When considering gamete formation, during meiosis the alleles segregate into different gametes randomly. Assuming that the individual is heterozygous for the given alleles A and b on the Z chromosome, each gamete produced has a 50 per cent chance of receiving either allele. Since the Z chromosome can be either with the A or b allele, the probability of a gamete from this individual having the A allele is 0.5 and the same applies for the b allele. However, because the individual is homozygous for the Z chromosome, and the question specifies only the alleles A and b (ignoring W), all gametes from this individual will carry a Z chromosome.

User Arsen Zahray
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