Who is "more" biologically related to me, my full cousin or a half niece?

Question

Would a cousin from my mothers side of the family, full blooded (my first cousin) or a "half" niece from my mother's first marriage, my half sister's daughter who isn't related to my father...Been pondering this for a while now and it's driving me insane :P Thanks in advance! I'm leaning towards the first cousin since genetically we have the same blood, right?

Answer 1

Genetically speaking, you share the same amount of genes with your first cousin as with your half niece.  You have approximately 1/8 of your genes in common with each of them.  You are no more related to one of them than the other.

It's all a matter of multiplying probabilities.  You share half your genes with your mom, who shares approximately half her genes with her sibling (your aunt or uncle), who shares half his or her genes with his or her child (your first cousin).  1/2 x 1/2 x 1/2 = 1/8.

For the other relationship, you do the same thing.  You share half of your genes with your mom, who shares half of her genes with her daughter from another marriage (your half sister), who shares half of her genes with her daughter (your half niece).  1/2 x 1/2 x 1/2 = 1/8.

Answer 2

I'm going with ... they're about the same.

Half sister would be 1/4 you.  Her daughter would be 1/8 you.

Your mother is 1/2 you.  Your aunt or uncle would be 1/4 you.  Your cousin would be 1/8 you.

Answer 3

100% cousin!!

Answer 4

Cousin definately! Explanation....you cousin has 1/2 your moms blood and someone elses, when your niece has 1/2 your mom and some other dude besides your dad, then 1/2  your half sister's blood, making almost 1/4. I guess that makes sence!