Question

A family consisting of a mother (I-1), a father (I-2), and three children (II-1, II-2, and II-3) are genotyped by PCR for a region of an autosome containing repeats of a 10-bp sequence. The mother carries 16 repeats on one chromosome and 21 on the homologous chromosome. The father carries repeat numbers of 18 and 26.

Identify all the possible genotypes of children of this couple by specifying PCR fragment lengths in each genotype.

Accepted Answer

Hey, everyone. Let's take a look at this question together. Tack DNA polymerase is the most commonly used enzyme in PC R. Which of the following is a required cofactor for thermostable DNA polymerase. Is it answer choice. A primer answer choice B DNA base, answer choice C magnesium or answer choice D DNA template. Let's work this problem out together to try to figure out which of the following is a required cofactor or thermostable DNA polymerase. So we are talking about tack DNA polymerase, which we know that Tack DNA polymerase is a thermostable enzyme and it requires a cofactor for stability. So of the following answer choices, which one is a co factor that provides that stability or thermostable DNA polymerase. Well, answer choice A says primer which we know that primers are short pieces of DNA that are used to initiate PC R. And since those primers are used to initiate PC R, they are not used for that stability. So answer choice A is incorrect answer choice B DNA base, we know that DNA bases are those building blocks of DNA. So answer choice B is incorrect since it is not related to the stability of TAC DNA polymerase. And answer choice D says DNA template, which we know that the DNA template is that original DNA strand that is used as a template in PC R. And so it is not used for stability. So answer choices A B and D are all incorrect. And we note that answer choice C magnesium is the correct answer by process of elimination. Since we know that magnesium helps stabilize the enzyme and facilitate that polymerization reaction. And without magnesium, the enzyme would not be able to function properly. So, magnesium is that required co factor for stability for thermostable DNA polymerase. And it is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

Watch next