A family consisting of a mother (I-1), a father (I-2), and three ...

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.

Following the layout of Figure 7.26c, which aligns members of a pedigree with their DNA fragments in a gel, draw a DNA gel containing the PCR fragments generated by amplification of DNA from the parents (I-1 and I-2). Label the size of each fragment.

Accepted Answer

Hey, everyone. Let's take a look at this question. Together. The DNA fragments are separated based on their sizes and charges in gel electrophoresis. The standard reference which contains DNA fragments of known lengths is called, what is it? Answer choice. A electrophoresis guide answer choice B protein gels, answer choice C DNA ladder or answer choice D standard wells. Let's work this problem out together to try to figure out what the name is for the standard reference in gel electrophoresis, which contains the DNA fragments of known lengths. So we are talking about gel electrophoresis. And so here we have a diagram that shows gel electrophoresis or we have our Agarose gel, which is the gel that is used in gel electrophoresis us. And we have our wells that we insert the DNA into and we have our electric source where we have a negative electrode at the top and a positive electrode at the bottom. Since the movement of DNA is from the negative electrode towards the positive electrode, and we know that larger DNA moves slower towards that positive electrode, which is what allows us to know the sizes and the charges of those DNA fragments in gel electrophoresis. But in order to know the specific lengths of those DNA fragments, we use this standard reference which contains those DNA fragments of the known lengths to compare it to the DNA fragments that we do not know the lengths of. And so this standard reference which contains those DNA fragments of the known lengths is called the DNA ladder, which serves as the reference of the known lengths to compare the unknown lengths to. Which means that answer choice C DNA ladder is the correct answer. Since that DNA ladder is the standard reference which contains the DNA fragments of the known lengths so that we can determine the unknown lengths of our DNA fragment. And so answer choice C DNA ladder is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

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