eli5: if you inherit 50% of your genes from your father and 50% from your mother, what stops you from getting two of the same gene, and missing one? also why do siblings look different?

Question

eli5: if you inherit 50% of your genes from your father and 50% from your mother, what stops you from getting two of the same gene, and missing one? also why do siblings look different?

In: Biology

Answer 1

Your genes are grouped up into 46 larger structures called chromosomes, and they’re in pairs.

So when you inherited half your genes from your mother you didn’t just get a random selection of 50% of her DNA, you got one copy from each set of chromosomes.

Then you get another copy from your father.

23 pairs, 46 chromosomes.

That ensures that every human baby has the complete set.

Now most of your genes *are* copies, there’s very little genetic variation between individuals. Sure a person in Egypt and a person in Japan can have different colored hair or eyes, but they have the same cellular metabolic pathways.

Most of this stuff is critical to life that can’t be changed, only the superficial details can vary much between individuals or even entire species – a mosquito shares a lot of those cell metabolism genes with you too because they’re so important.