Is it possible to be more genetically related to an aunt than a parent?

This does a good job of explaining the answer to your question. Basically, everyone has two sets of genes from their parents. When we reproduce, we pass half of them. But…we don’t know which half. So you could pass your mom’s gene that causes blue eyes with one child, and your dad’s gene for brown eyes with the second child. This is what they mean when they say that you have a 50% chance – just think of the decision of which gene you get being based on a coin flip. Each time it flips…there’s a 50% chance that it will land on mom or dad. Considering the number of time the coin gets flipped, the average works out to about half of one, half of the other.

Pretty much only through incest. Lots of things are possible through incest. You could share more than 50% of genetic material with an aunt, and have two heads. Win/win.

I was going to say, only if there are skeletons in the family closet! :-/
It’s possible! :-/

In Alabama!

As for why you and your brother/sister aren’t identical:

For each and every one of those traits that make up a human being, each parent passes on one of two possibilities. For example, let’s deal with eye color. Dad might have inherited a Brown eyed gene from his father, and a Blue eyed gene from his mother. Consequently, Dad has brown eyes (because brown is dominant over blue). Mom inherited blue eyed genes from both of her parents, and so has blue eyes.

When Mom and Dad reproduce, the egg and sperm cells have exactly ½ of the total number of genes the rest of their cells have. Random chance decides which of the genes they inherited from their parents go into each egg or sperm cell. Some of Dad’s sperm will have a blue-eyed gene, some will have a brown-eyed gene. (In this case, all of Mom’s eggs will have a blue-eyed gene, since she got blue-eyed genes from both parents)

Now Mom and Dad reproduce. By random chance, the eye-color gene on the sperm that happens to fertilize Mom’s egg has Dad’s brown-eyed gene. Mom’s egg, of course, has a blue-eyed gene. Consequently, the new fetus will have brown eyes (again, because Dad’s brown eyed gene is dominant over Mom’s blue-eyed gene).

But now a year later, Mom and Dad reproduce again. Hello, sibling! This time, by random chance, the eye-color gene on the sperm that happens to fertilize Mom’s egg has Dad’s blue-eyed gene. Again Mom’s egg has a blue-eyed gene as well. This time, the new fetus will inherit two blue-eyed genes, and consequently have blue eyes.

Both you and your sibling came from the same parents. But random chance decides which of the genes your father inherited were carried by the sperm that created you, and which were carried on the sperm that created your sibling.

Now when you take all those possible combinations – genes for eye color, hair color, height, ear lobe connectivity, ability to curl your tongue, everything that makes a person a person – and you realize you might get any one of the two your mother has plus any one of the two your father has, and then whichever one is dominant takes control…. there are countless possibilities for the final product.

Of course it is possible. Parents come in many forms. They may be adoptive, a birth might be via an egg or sperm donor, and there are step parents as well. All of these are parents nonetheless. If a couple find they are infertile, an aunt on the mother’s side might well be asked to donate an egg; in an extreme case you might also have sperm donated by an uncle on the father’s side, so the aunt and uncle are the genetic parents.

Well, you get 50% of both your parents DNA and siblings can share extreme amounts of DNA so your aunt could share 48% DNA with your mother and for example 10% with your father through pure chance. If your parents are different enough this would be enough for you to be more closely related to your aunt than to your parents.

Genetics are in this aspect very much like the lottery, you can win anything but the more you ask for the less likely it is you’ll actually get it.

@iamthemob I would point out that gene recombination is usually more complicated than a true 50–50 mix. Geneticists often use tables to determine what the probability is that the offspring will have a certain trait (like eye color). These tables can be quite complicated. (They also have a special name that is escaping me at the moment…)

@camertron – of course. However, there’s no real need to get into the mechanics of fertilization and recombination until we get past that first bit – the “wait, what?” part. ;-)

The short and long of it… no. Relatedness is a statistical value and has constant values for your parents (50%) no ifs ands or buts. Your aunt may be genetically identical to your mom and thus also 50% related. Since your grandparents are 25% related to you, assuming no recent inbreeding, then your aunt is somewhere between 25 and 50% related. The exact value is undeterminable with out extensive genetic tests. This accounts for recieving variable amounts of genetic material from one grandparent or the other. Statistically, it is impossible for your aunt and your father to create the same child as your mom and your father. Good luck!

@tigress3681 Statistically impossible?
Nevermind, I don’t even care where you got that.

It depends how you look at it. See

http://en.wikipedia.org/wiki/Genotype-phenotype_distinction

It is possible that there are more similarities with an aunt phenotypically.

Thank you all… xx