Approximately what percentage of their genes do first cousins share?

Question

Approximately what percentage of their genes do first cousins share?

Answer 1

parent * full sibling * child = cousin

1/2 * 1/2 * 1/2 = 1/8

Answer 2

I'm no geneticist, but let's see:  the parents of first cousins are siblings--therefore, they have the same parents.  Their children have half their genes--so, I'm thinking 25%?  I could be wrong.

You realize that the odds are that there would be no genetic problems with children of a union of first cousins.  That would only happen if there were a genetic defect in the family, and even then, it would not be a certainty; it would only be more likely.

Incest is not an almost-universal taboo because ancient people knew anything about genetics.  It was about expanding a community by marrying outside of that community.

Answer 3

Many of their genes should be the same, however, with crossing over and random mutations, there would be many, many differences.  No generalisation can be made.

Answer 4

multiply by 1/2 each time you go up until you get to the common ancestor, then 1/2 each time you go down. If they have two common ancestors, you do that twice and then add them up. Let's assume their dads are brothers.

(cousin1 = 1)(dad1 = 1/2)(grandpa = 1/2)(dad2 = 1/2)(cousin2 = 1/2) = 1/16

(cousin 2 = 1)(dad2 = 1/2)(grandma = 1/2)(dad1 = 1/2)(cousin1 = 1/2) = 1/16

1/16 + 1/16 = 1/8

Answer 5

ew dont date your cousin >< no matter how many or few genes you share