Anhidrotic ectodermal dysplasia is an x linked recessive...

Anhidrotic ectodermal dysplasia is an X-linked recessive disorder in humans characterized by small teeth, no sweat glands, and sparse body hair. This trait is usually seen in men, but women who are heterozygous carriers of the trait often have irregular patches of skin with few or no sweat glands (see the illustration below). a. Explain why women who are heterozygous carriers of a recessive gene for anhidrotic ectodermal dysplasia have irregular patches of skin lacking sweat glands. b. Why does the distribution of the patches of skin lacking sweat glands differ among the females depicted in the illustration, even between the identical twins?

Transcript

00:01 This question contains two parts.

00:02 For the first part of the question, we will explain why women, who are heterozygous carriers of a recessive gene for anhydrotic ectodermal dysplasia, have irregular patches of skin lacking sweat glands.

00:15 Well, this is all due to the fact that in females, we see random x inactivation.

00:31 So the disorder, anhydrotic, ectivation, so the disorder, anhydrotic, dermal dysplasia is going to be an x -linked recessive disorder, meaning that the disorder will be manifested based on an allele that is present on the x chromosome.

00:51 Now, depending on whether or not we inactivate that x chromosome, we have this 50 -50 shot in inactivating it, so in females there will be a random inactivation of the x chromosome across the body.

01:03 So in every single cell there will be an x chromosome, meaning that if you're a random in we are to inactivate one, like say x chromosome number one in one particular cell.

01:16 So if we are to take a look, let's say that this is someone's arm, right? the arm is going to have a lot of cells in it.

01:23 Let's say that this group of cells is going to inactivate chromosome x chromosome 1.

01:30 And then this group of cells is going to inactivate x chromosome 2, then 1 and 2 and 1, 2, and 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2.

01:49 And now we see that depending on which x chromosome we inactivated, we will, well, let's say that this is going to be the recessive one, so we could call it x, superscript little r, is going to be our disorder.

02:06 And it is going to be inactivated in, let's say, each area that is going to be represented by chromosome 1...

Question

Please give Ace some feedback