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

The genes are bundled into packages called Chromosomes. You get 1 set of Chromosomes from each parent, but each (except the Sex Chromosomes in Men) comes in a pair, with 2 copies of each gene, 1 from each parent.

As for why siblings look different, on average, they only share ~~25~~50% of your DNA (well except for the 99.9% you share with ALL of humanity). That makes differences.