# Relatedness **URL:** \ **Category:** Factual Questions\ **Created:** [January 28, 2025, 10:29pm UTC](https://boards.straightdope.com/t/relatedness/1013551 "2025-01-28T22:29:38Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [January 31, 2025, 3:20am UTC](https://boards.straightdope.com/t/relatedness/1013551/22 "2025-01-31T03:20:06Z")
> [@Chronos](#): > > So you could end up with an individual whose ancestry is mostly one species, My understanding of this is that we are, pretty much, aside from some far south African communities, part Neandethal. Gene migration spread back to Africa once we, as a selection of species, [realised it was possible.](https://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals) ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [January 31, 2025, 3:22am UTC](https://boards.straightdope.com/t/relatedness/1013551/23 "2025-01-31T03:22:28Z")
> [@engineer\_comp\_geek](#): > > 70 percent gets you in the realm of humans vs. worms or slugs I, for one, welcome our slug-human hybrid overlords. Also banana-human hybrids, which is the most common claim as to [shared DNA](https://www.pfizer.com/news/articles/how_genetically_related_are_we_to_bananas) I have heard. I am not totally convinced.\* Wait! [Banana slugs](https://en.m.wikipedia.org/wiki/Banana_slug) exist. We are doomed. \* this is satire. I have never heard this claim. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [January 31, 2025, 5:48am UTC](https://boards.straightdope.com/t/relatedness/1013551/24 "2025-01-31T05:48:14Z")
Imagine this as a thought exercise. A grouping of creatures travel down an evolutionary path, mixing with others of their ilk nearby, but generally (unless we get to a ring species) they are essentially the same species. They keep mixing, and one reason species differentiate is to ensure like is attracted to like.\* Now it’s possible the speicies is separated, and some group is isolated on a tropical island subject to such intense environmental pressures that they evolve to be different and present as a different species - or maybe they end up with one member duplicating a chromosome and maange to continue and procreate such that this becomes a characteritic of the species. Meanwhile, back at the ranch, the existing original species is so spread out that some of them - on the shore near the island - are more related to this new species than they are to the distant members of their species. But generally - no. The species is a group that evolved together, choosing to mate with members who displayed the same characteristics that ensured survival. This selection for shared characteristics ensures the coherence of the species. \*There’s a concept off “differentiation”. One speculation is that sapiens sapiens has nice chins to distinguish from neaderthal and others - people are attracted to what’s the norm for them, so something that distinguishes themselves from neighbouring subspecies ensures that mating attraction etc. is more “optimal” - also a species survival mechanism. Also in theory why bird species develop distinctive coloration between species - so they know they are chasing compatible mates… ---
**Author:** ![Richardpurvey](https://avatars.discourse-cdn.com/v4/letter/r/3ec8ea/32.png) [@Richardpurvey](https://boards.straightdope.com/u/Richardpurvey)\ **Post date:** [February 4, 2025, 12:49pm UTC](https://boards.straightdope.com/t/relatedness/1013551/25 "2025-02-04T12:49:14Z")
Thank you! ---
**Author:** ![Richardpurvey](https://avatars.discourse-cdn.com/v4/letter/r/3ec8ea/32.png) [@Richardpurvey](https://boards.straightdope.com/u/Richardpurvey)\ **Post date:** [February 12, 2025, 8:06am UTC](https://boards.straightdope.com/t/relatedness/1013551/26 "2025-02-12T08:06:43Z")
Thank you so much for that answer! ---
**Author:** ![Richardpurvey](https://avatars.discourse-cdn.com/v4/letter/r/3ec8ea/32.png) [@Richardpurvey](https://boards.straightdope.com/u/Richardpurvey)\ **Post date:** [April 27, 2025, 5:30pm UTC](https://boards.straightdope.com/t/relatedness/1013551/27 "2025-04-27T17:30:17Z")
Some very hekpful answers and thank you! I am also satisfied having read the brilliant article - Genealogical Perspectives On The Species Problem David A Baum and Kerry L Shaw It argues focusing on the genealogical histories of genes rather than measuring relatedness in terms of recency of common organismic descent. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 29, 2025, 8:03pm UTC](https://boards.straightdope.com/t/relatedness/1013551/28 "2025-04-29T20:03:11Z")
> [@Richardpurvey](#): > > So they all share an INDIVIDUAL ancestor of that species? > [@engineer\_comp\_geek](#): > > If you go back far enough, everything goes back to a common ancenstor. Yeah, but the common ancestor for a species will not have been a member of that species, because speciation happens to populations (maybe not for organisms that reproduce asexually, parthenogenetically etc - speciation could begin with a single individual in those cases) [Previous page](https://boards.straightdope.com/t/relatedness/1013551.md?page=1)