Question

Restriction maps of two alleles of the cystic fibrosis gene are shown below. The restriction enzyme EcoR1 cuts the normal allele at the site indicated with a vertical arrow. Which fragment(s) would be detected on an electrophoresis gel following EcoR1 digestion of the region from a person who is heterozygous for the two alleles? (Picture atached)

1 kb only
4 kb only
5 kb only
1 and 4 kb only
1, 4, and 5 kb

Answer 1

Oh, and please explain how/why. I need to learn how to do this, lol. :) Thanks!

Answer 2

well lets start from basics - what heterozygous tells us?

Answer 3

Well, i guessed 1 & 4 but i want to make sure. Hereozygous means "
different".. so it would have to be either 1, 4 and 5... or 1 and 4. right?

Answer 4

Heterozygous has no direct relation to these numbers - it tells us what types of gene alleles are present in certain individual.

Assuming we have only two types N (normal) and C (Cystic fibrosis) which of the following individuals is heterozygous? NN, NC, or CC ?

Answer 5

Oh. NC :)

Answer 6

Yep! NC it is - this means that human has both alleles for Normal and cystic fibrosis. Now they both are 5kb initially, but what would happen when you use EcoR1 on both of them? =)

Answer 7

Uhmm. It would be 5kb only? Does the EcoR1 basically remove the two other genes? Or am I reading it incorrectly.

Answer 8

Or all 3? Now I'm thinking 1, 4, and 5.

Answer 9

Did you ever figure out the answer to this question? I'm stuck.......