Geneticists: How is this possible?

Question

My hair is brown.

My mother's hair is black, and in her family everybody has either red or black hair.

My father's hair is blond. His family has either black or blond hair.

My brother and sister both have black hair. My little sister has red hair.

Why do I have brown hair? The only person in my family with brown hair is my cousin, but that's because her dad has brown hair, and he's not from my family.

Could I possibly be adopted?

Also, I have Asperger's Syndrome, though there's no Autism history in my family.

Thank you

Answer 1

Human hair colour is not, in anyway as simple as eye colour. threre are many genes that contribute to hair colour and you most likely received a mix of the black and the blonde gene which, in the end comes out brown.

Also asperger's syndrome is a recent label for a very mild form of autism. Your fathers family most likely has a history of it but since the label is so recent, none of them would have been diagnosed with it besides for you.

I would say you are not adopted but asking would be the only way to know for certain.

Answer 2

Everything is determined from a seemingly random set of genes passed down from your ancestors. thats the basics of it. Your unique set of genes could be passed down from distant family members who's genes have just been recessive for several generations.

I'm half black/ white, but i look full black in terms of skin tone, body, and face.

With the exception of my hair, which is in fact straight.

The autism could be developed through genetic mutation or just the way you developed and is perhaps unique to you only.

My dad stutters, but no one else in the family ever had any speech impediments, its just something he developed.

Answer 3

The brown eyes is suspicious.  There are two primary genes involved in eye color: B and G.

To have brown eyes, you need to have at least one B allele, so your genotype could be: BBGG, BbGG, Bbgg, BBgg, etc.

If you don't have a B allele, you end up with green or blue eyes.

bbGG and bbGg = green

bbgg = blue

So, if your mom has green eyes and your dad blue, then their genotypes would be something like bbGg x bbgg.  They have no B alleles to pass on and therefore can't have children with brown eyes.  

However, we do know that environment plays a role in the expression of genes, and, there are other genes we know very little about involved in eye color, so never say never when it comes to what's possible with genes.  It's also possible that a mutation could have occurred in one of your parents s*x cells that created the B allele from a b allele.  (This is a remote possibility though because not only are mutations rare, but this would be a gain-of-function mutation which are much rarer.)

If your parents both have blue or green eyes, it is incredibly unlikely they could naturally have a child with brown eyes.