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

You inherit 23 chromosomes from your mom, and 23 from your dad. But they also inherited that number from your grandmothers and grandparents. So siblings are different because when your dad gives you 23 chromosomes, it could be 10 from you grandma and 13 from your grandpa, or 22 and 1, they’re randomly separated. So even though both you and your sibling have 23 chromosomes from your dad, it is different combinations of those 23. The same thing happens with your moms chromosomes.

For example, I have brown eyes and my brother blue eyes. I could have my grandpas chromosomes of brown eyes, and my brother got my grandmas, that has blue eyes (it’s more complicated that this).