The Punnett square above shows that all of the female offspring will have normal

Question

The Punnett square above shows that all of the female offspring will have normal vision, males will have normal vision, and the other ½ of the males will be colorblind. of the 1. Hemophilia is an X-linked recessive when the person is wounded or bruised. If a woman with hemophilia marries a man with n clotting, what would be the expected phenotypes of their male and female children? Answer: trait that causes an individual to bleed freely instead of clotting ormal blood 2. A man and his wife both have normal color vision, but they have a daughter who has red-green color blindness, an X-linked recessive trait. The man sues his wife for divorce on grounds of infidelity. Use a Punnett square to support the man's case. Answer 3. In fruit flies, eye color is a sex-linked trait carried on the X chromosome. The dominant eye color is red and the recessive is white. If you cross a red-eyed female who is heterozygous with a male who has white eyes. What would be the sex and eye color of the resulting offspring? Answer: 4. Suppose that a gene (d) is X-linked, recessive, and lethal. A man marries a woman who is heterozygous for this gene. Do the Punnett square and calculate the ratio of male and female offspring of this couple Answer

Explanation / Answer

1) Since hemophilia is a X linked recessive trait, a woman will express the disorder only when she has two recessive allele in her genotype, since a female has two X chromosomes.

So, The genotype of a hemophiliac woman will be - XhXh

A male has only one X chromosome and the genotype of a normal man will be - XHY

When crossing both with punett square:

Genotype ratio - XHXh: 2 and XhY: 2 = 2:2 = 1:1

Phenotype ratio - 2 female carriers : 2 hemophiliac male = 2:2 = 1:1

When. a female has only one recessive allele for the disease, then she will be a carrier and will not express the disease and since males have only one X chromosomes, inheriting one recessive X allele will be sufficient to cause the disorder in them. So, when a hemophiliac female reproduces with a normal male, all of the female offsprings will be a carrier and all of the male offsprings will express the hemophilia disorder.

XH Y Xh XHXh XhY Xh XHXh XhY

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