Question

Genetics question!! Please help with these 3. Thanks

A woman with Turner syndrome (X0-only one X-chromosome) is also colorblind (an X-linked recessive phenotype). Both of her parents have normal color vision. This women's karyotype and genotype could have arisen by: a) a mutation in her mother's X-chromosome b) non-disjunction in mitosis c) non-disjunction in meiosis 1 in her father d) non-disjunction in meiosis 2 in her mother e) non-disjunction in meiosis 1 in her mother 10. Mitochondrial genomes a) replicate in synchrony with the nuclear genome b) contain both dominant and recessive alleles c) can vary within an individual d) exist as a single copy per cell e) have many sex-linked genes 11. An important, usually untested, assumption of genome wide association studies is: a) that the alleles of genes responsible for the trait are common in the general population b) that relatively few genes contribute to the phenotype c) that males are more likely than females to express the trait than in others d) that the trait is more common in some regions of the world than in others e) that the trait is not affected by environmental variance

Answer 1

Answer:

9).

a). a mutation in her mother’s X-chromosome

b). non-disjunction in meiosis 1 her father.

Explanation:

XC=Normal chromosome; Xc= Color blind chromosome

XCXc (normal mother) x XCY (normal father)----Parents

Due to non-disjunction in meiosis 1 of father produces two types of sperms, 22+XCY & 22+O.

Mother produces two types of eggs, 22+XC and 22+Xc.

22+Xc egg fuses 22+0 sperm and produces 44+Xc0 zygote(colorblind & turners syndrome woman).

10). d). Exist as a single copy per cell

Explanation:

Mitochondrial genome will be transferred from mother to progeny as the zygote receives mother cytoplasm only. The progeny will have a single copy of mitochondrial genome.

11). a). That the alleles of genes responsible for the trait are common in the general population.