The Mystery of Missing Sleep Heritability

Why can we prove that our sleep patterns are inherited, but we still can't find the specific

genes responsible? This is the great mystery of "missing heritability." Twin studies tell

us that traits like sleep duration and quality are highly heritable—sometimes over 50%—meaning

they are definitely passed down through families. However, all the specific

gene variants discovered so far explain less than 5% of that variation. The rest of that

genetic influence is "missing" from our current maps. Scientists believe the answer lies

in thousands of tiny DNA differences working together, or even epigenetics, where your environment

actually changes how your genes are expressed without changing the DNA itself.