A woman's father has ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder producing mental deterioration if not properly treated. The woman's mother is homozygous for the wild-type allele.

If the woman has a daughter with a man who does not have OTD, what is the chance the daughter will be a heterozygous carrier of OTD? What is the chance the daughter will have OTD?

Question

A woman's father has ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder producing mental deterioration if not properly treated. The woman's mother is homozygous for the wild-type allele.

Identify a male with whom the woman could produce a daughter with OTD.

If the woman has a daughter with a man who does not have OTD, what is the chance the daughter will be a heterozygous carrier of OTD? What is the chance the daughter will have OTD?

Accepted Answer

Hi, everyone. Welcome back. Let's look at our next problem. It says if in females, a variant in one of the two X chromosomes is enough to cause the disease, this condition is considered to be and we have choices of excellent recessive, excellent dominant, autism or recessive and autism will dominant. But we're told right, in our problem that the variant is on an X chromosome. So we can go ahead and eliminate choice. See autism all too possessive and choice. D autism will dominant. It's not on an autism, it's on the X chromosome. And then it says that a variant in one of the X chromosomes is enough to cause disease. So that makes this inheritance choice be excellent dominant because it only needs one affected a little to express the phenotype as opposed to choice. A which will eliminate excellent recessive, which would need two copies would need both X chromosomes to be affected before a female would have the disease. Just an interesting side note. We often because we often look at examples of excellent recessive traits. We kind of connect excellent traits with being more frequent in males, but that is only the case for the excellent recessive traits, they occur more frequently in males since males just have the one X chromosome and therefore only need to inherit one allele to express the trait. Whereas females need to inherit from both parents, but excellent dominant traits will be seen more often in females. Because females with their two X chromosomes, if they only need to inherit one copy, can inherit it from either of their parents, mother or father. A male only inherits the X chromosome from his mother. And therefore will only has a chance to inherit from the mother, will never inherit from an affected father. So that's why you'll see excellent dominant traits appearing more frequently in females. But again, in females, a variant in one of the two X chromosomes is enough to cause the disease. This condition is considered to be choice B X linked, dominant. See you in the next video.

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Key Concepts

X-Linked Recessive Inheritance

Genotype and Phenotype

Punnett Square