Timeline for How do we know the human species arose in Africa?
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30 events
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| Apr 5, 2021 at 18:26 | vote | accept | Faheem Mitha | ||
| Apr 13, 2017 at 12:48 | history | edited | CommunityBot |
replaced http://biology.stackexchange.com/ with https://biology.stackexchange.com/
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| Jul 22, 2015 at 9:52 | review | Suggested edits | |||
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| Jul 22, 2015 at 7:05 | comment | added | Luaan | @yters In any case, this is really getting dragged out. Perhaps you'd like to post a question specifically about Mitochondrial Eve? I'm sure there's plenty of people who can explain this better than me - I'm no expert on human evolution or biology in general. | |
| Jul 22, 2015 at 7:03 | comment | added | Luaan | @yters It is indeed possible that there wouldn't be a MitE for Homo sapiens sapiens, for example. But eventually, outside of a given species, you do come to a single ancestor - maybe it was some hominid, or a fish. But with each generation, the probability of only having a single (mitochondrial) ancestor grows. If you only have sons, your MitE line just dies out, ditto if you die. As far as I know, we don't actually know if MitE was an anatomically modern human - it's not like we have her fossillised remains. Her identity is based on probabilistic analysis of human mitochondrial lines. | |
| Jul 22, 2015 at 6:58 | comment | added | Luaan | @yters Note how the single mitochondrial "ancestor" appears so long after humans did. In the beginning, there have been a lot of different mitochondrial lines - if we take the Homo genus as a whole, that's been around 10 million years, if we go from the point where modern humans diverged from Neanderthals that's around 500 thousand years. Interestingly, anatomically modern humans actually arose around the same time as MitE. But even at the time of MitE, there has been tons of different mitochondrial lines. It's just that one won out in the end - all modern Mit lines are descendants of MitE. | |
| Jul 22, 2015 at 1:29 | comment | added | Michael | @Resonating If I had a time machine, tracing ancestral lines would indeed be an interesting use for it... | |
| Jul 21, 2015 at 22:28 | comment | added | Resonating | @yters Yes and no. At any given point, there's a set of women that are the 'mitochondrial eves' of that point in time. These women between them are mitochondrial ancestors of all living humans. At this point in time, it's all mothers. If you go back further it's all maternal grandmothers. If you go back far enough the set keeps getting smaller, until it's one person. Any further back and it stays one person. Come to chat, we can back and forth faster there. | |
| S Jul 21, 2015 at 18:46 | history | suggested | Faheem Mitha | CC BY-SA 3.0 |
Minor formatting/punctuation adjustments (no space after opening bracket, capitals after colons).
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| Jul 21, 2015 at 18:41 | comment | added | WYSIWYG | @yters There could have been a person but mitochondrial genome can also accumulate mutations and the rate of mitochondrial mutations is higher than that of the nuclear genome. All I said is that 'mitochondrial eve' is a hypothetical person. I said that I think the term "eve" can be misleading. | |
| Jul 21, 2015 at 18:26 | comment | added | yters | @WYSIWYG, correct me if wrong, but you are still saying this calculation is meant to pick out a single female individual in the past with whom everyone shares their mitochondrial DNA, correct? The calculation is not just a mathematical construct, but is meant to refer to a real individual in the past? | |
| Jul 21, 2015 at 18:24 | comment | added | yters | @Luaan, thanks that makes more sense. So, to restate what you are saying, there is a single female in the past that everyone shares mitochondrial DNA with. It still doesn't make sense that there has to be a single female. Mathematically, it seems there could be many "mitochondrial eves" from the same period. | |
| Jul 21, 2015 at 17:28 | review | Suggested edits | |||
| S Jul 21, 2015 at 18:46 | |||||
| Jul 21, 2015 at 17:12 | comment | added | Lightness Races in Orbit | @FaheemMitha: :) | |
| Jul 21, 2015 at 17:09 | comment | added | Faheem Mitha | @LightnessRacesinOrbit I see. Thanks for the clarification. I just remarked to Resonating that apparently we don't watch enough Battlestar. | |
| Jul 21, 2015 at 17:01 | comment | added | Lightness Races in Orbit | @Faheem: en.wikipedia.org/wiki/Hera_Agathon | |
| Jul 21, 2015 at 16:49 | comment | added | Faheem Mitha | @LightnessRacesinOrbit We're wondering (in chat) what you meant by that. Enlighten us, please. | |
| Jul 21, 2015 at 15:59 | comment | added | Lightness Races in Orbit | Mitochondrial Eve was called Hera. | |
| Jul 21, 2015 at 13:35 | comment | added | Resonating | @Colombo Mitochondrial Eve is a single human female who is guaranteed to have existed based on what we know about how genetics works. You're confusing imprecision in the measurement technique for imprecision in the measured thing. If you had a time machine Mitochondrial Eve would be time-consuming but trivial to locate precisely. | |
| Jul 21, 2015 at 13:32 | history | edited | Resonating | CC BY-SA 3.0 |
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| Jul 21, 2015 at 13:21 | comment | added | Resonating | @Catalept that's not quite right, you're thinking of something else I think. Most recent common female ancestor, maybe? | |
| Jul 21, 2015 at 10:29 | comment | added | WYSIWYG | @yters Mitochondrial eve is not a person or a group of persons (in fact I hate these creationistic connotations). It is basically a phylogenetic calculation of the Last Common Ancestor of human mitochondria (which are specifically maternally inherited). IMO addressing to this concept as her/she can be highly misleading. Resonating: you should clarify this in your answer. | |
| Jul 21, 2015 at 6:52 | comment | added | Luaan | @yters It's not made explicit in the answer, but mitochondrial DNA is passed almost exclusively through the female line (sperm usually only has one or two mitochondria, if any at all, while the ovum has more like fourty). There has been many lines of mitochondrial DNA, but as soon as a mother only had sons, her line was broken. Add to this how many near-extinction catastrophes humans went through (apparently, there's been times when there were only a few thousand humans on the planet!), and it isn't all that suspicious that you can trace one line that's running in all of us. Others died out. | |
| Jul 21, 2015 at 5:35 | history | edited | Resonating | CC BY-SA 3.0 |
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| Jul 21, 2015 at 4:19 | comment | added | Catalept | It's not that all ancestral lines go through Mitochondrial Eve's exclusively, it's that she's the most recent person which everyone's 'set of all ancestors going back X years' can be expected to have her in it. | |
| Jul 21, 2015 at 2:19 | comment | added | yters | Why would matriarchial lines terminate at one person in the past instead of there being multiple lines? That doesn't make a lot of sense to me. It would either mean that matriarchial lines never crossed, or that initially there was only a single woman. Does the term "mitochondrial eve" actually refer to a group of women? | |
| Jul 21, 2015 at 0:37 | comment | added | Colombo | No, mitochondrial eve isn't real women, it is computer reconstruction according to genetic theories, mutation rate, inheritance and so on. Change one parameter (estimated effective population size, although that one have loose connection with real population size as well) and you have different estimate of Mitochondrial Eve. | |
| Jul 20, 2015 at 22:55 | comment | added | MastaBaba | Does this mean mitochondrial eve had multiple kids with multiple men? | |
| Jul 20, 2015 at 19:25 | history | edited | Resonating | CC BY-SA 3.0 |
I know how to use words, I promise.
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| Jul 20, 2015 at 19:16 | history | answered | Resonating | CC BY-SA 3.0 |