From 8c2cd5abfdcf2e789886f9ed0f3ee1ad53b32b69 Mon Sep 17 00:00:00 2001 From: Kayce Basques Date: Tue, 23 Jan 2024 12:40:15 -0800 Subject: [PATCH] Migrate the ancestors post --- src/blog/ancestors.md | 44 ++++++++----------------------------------- src/index.md | 1 - 2 files changed, 8 insertions(+), 37 deletions(-) diff --git a/src/blog/ancestors.md b/src/blog/ancestors.md index ea8d2e3..26d0281 100644 --- a/src/blog/ancestors.md +++ b/src/blog/ancestors.md @@ -1,41 +1,13 @@ --- layout: base.njk -title: "You have thousands of ancestors from the 1500s" --- -# {{ title }} + -I usually think about lineages from the perspective of the ancestor. E.g. my -grandpa had 5 kids; those 5 kids produced 9 grandkids; those 9 grandkids -produced 3 great-grandkids (so far); 17 descendants in total. - -Over the last few days, I've been having fun thinking about the situation in -reverse, from the perspective of the descendant. Here's a quote from *Genes: -A Very Short Introduction* by Jonathan Slack: - -> Also, when considering 'roots', some of the basic mathematics of inheritance -> needs to be borne in mind. With fully random matings the number of your -> ancestors doubles every generation. Ten generations ago (250-300 years) we -> might expect about 1,000 ancestors each contributing 0.1 percent of their -> total variants to your genome... when the number of ancestors exceeds -> 2,000-3,000 (12 generations would be about 4,000), it is likely that some -> ancestral sections of DNA have been lost altogether... by about 15 -> generations back many of the ancestors contribute no DNA variants at all but -> they are still ancestors on the lineage. So, even though we all have an -> ancestry running back to the origin of life on Earth, we do not necessarily -> have any DNA variants from most of our ancestors. - -[original version of this post]: https://web.archive.org/web/20230905030056/https://kayce.basqu.es/blog/ancestors/ -[Hacker News discussion]: https://news.ycombinator.com/item?id=37387341 - -(In the [original version of this post] I did a thought experiment here to calculate -when the number of ancestors starts to get nonsensical, i.e. if you double the -number of ancestors every generation there's a point where the number of ancestors -exceeds the total number of humans at that point. I've removed this thought experiment -because I think it distracts from my main idea. See the [Hacker News discussion].) - -[pedigree collapse]: https://en.m.wikipedia.org/wiki/Pedigree_collapse - -Your exact number of ancestors depends on how much [pedigree collapse] there -is in your lineage, but I'm pretty sure the basic premise of this blog post -holds: you've got a lot of ancestors. + diff --git a/src/index.md b/src/index.md index 0a21f90..57b53ca 100644 --- a/src/index.md +++ b/src/index.md @@ -27,6 +27,5 @@ I'm currently docs lead for [Pigweed](https://pigweed.dev). ## Blog * [Proper Full Moon songs](/blog/moon/) -* [You have thousands of ancestors from the 1500s](/blog/ancestors/) * [Why I'm taking a sabbatical](/blog/sabbatical/) * [My favorite words](/blog/words/)