How close are you related to your first cousin, genetically speaking?

Question

for ex. say that your and your identical twin are 100% related genetically, the genes/DNA wise, since you started off as completely identical , identical twins.

Say your and your father are 50% related, genetically speaking

also, for ex you and your mother are 50% or .5 , 1/2 related

you and a non-twin sibling also around 50%?

how about you and a first cousin? 25% ? but you share a set of grandparents, and we only have two sets of grandparents.

is it 50, 25 , 12.5 or what?

how much is nature? how much is nurture? 50-50 ?

Answer 1

Hmm.

I have two sons, my sister has two girls & a boy, so they are cousins

My sister and I are therefore 50% Dad, and 50% Mum

so our offsping are again 50% of their parents.

So I would say 1st cousins are about 25% related

I could be totally wrong, but it seems reasonable to assume that.

Bob