truthseeker1990 t1_iv3lpi0 wrote on November 5, 2022 at 12:50 AM

Reply to comment by byllz in Why don't we have Neandertal mitochondrial DNA? by nodeciapalabras

Isnt that odd? Or maybe just seems strange at face value. Nature rarely does anything in ones, why would all other lines vanish rather than have a mix of many lines

byllz t1_iv3r0vs wrote on November 5, 2022 at 1:34 AM

It is just a natural effect of lots of time combined with a population that doesn't grow quickly (as human population didn't for the majority of its existence). Take all the women living at a specific time in history and track each of their lines. Over time, just by random chance, one line will grow in members, which means another line will shrink. Every so often this random growing and shrinking will mean a line will shrink to nothing. However, once it is gone, it is gone forever, and so will never grow again. One by one they are snuffed out, until only one remains. And then Mitochondrial Eve moves forward in time. Since populations started growing considerably, lines have been dying out less.

truthseeker1990 t1_iv4fb4b wrote on November 5, 2022 at 5:26 AM

I understand some lines will snuff out and some will progress but why would there be exactly one line that survives? Wont you expect a mixture of lines to survive?

byllz t1_iv4g9lr wrote on November 5, 2022 at 5:38 AM

The answer lies in time. In a given period of time, just from random fluctuations there is a chance the number of surviving lines will decrease, based on how many lines are left and the population. So, given enough time, assuming the population doesn't grow, the chance the number of lines will decrease eventually approaches 100% just like theoretically you can flip a coin as many times as you want and always get head, the chance you will eventually get tails approaches 100%