Mathematics desk
< December 19	<< Nov \| December \| Jan >>	December 21 >

Welcome to the Wikipedia Mathematics Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 20

Predicting number of generations until every person is a direct decendant

Probabilistically speaking, how many generations from a given person must pass before it becomes likely that all people alive are the descendants of that person? --Puzzledvegetable^{Is it teatime already?} 01:17, 20 December 2019 (UTC)[reply]

A purely probabilitstic analysys assumes that a person's ancestors' pairings are purely random amongst a large population. This is becomong more valid in today's society, but historically it was most certainly not true because the majority of pairings took place within a small geographical area. You might like to read our article on Pedigree collapse. The answer to your question will depend very much on the location of the individual. The majority of people who have ever lived have no living descendants^{[citation needed]}. Dbfirs 01:37, 20 December 2019 (UTC)[reply]

The majority of people who have ever lived have no living descendants. If we factor out people who died before becoming old enough to have children (infant mortality having greatly declined in the modern era), would that still hold true? --Puzzledvegetable^{Is it teatime already?} 02:10, 20 December 2019 (UTC)[reply]

You might also find these interesting: Mitochondrial Eve, Y-chromosomal Adam, Most recent common ancestor. Loraof (talk) 16:35, 20 December 2019 (UTC)[reply]