4 ms·
Thing is, we are naturally not diverse at all (in part because our nearest ancestors with whom which we, at one time, did have reproduction compatibility with,
by speby 9y ago
Thing is, we are naturally not diverse at all (in part because our nearest ancestors with whom which we, at one time, did have reproduction compatibility with, are no longer here): https://www.ashg.org/education/pdf/geneticvariation.pdf https://www.ashg.org/education/pdf/geneticvariation.pdf
Specifically, modern humans have, on average, less than 0.1% of differences in their DNA amongst each other:
"How diverse are we?
Perhaps the most widely cited statistic about human genetic diversity is that any two
humans differ, on average, at about 1 in 1,000 DNA base pairs (0.1%). Human genetic
diversity is substantially lower than that of many other species, including our nearest
evolutionary relative, the chimpanzee. Genetic diversity is a function of a population's
"age" (i.e., the amount of time during which mutations accumulate to generate diversity)
and its size. Our genetic homogeneity implies that anatomically modern humans arose
relatively recently (perhaps 200,000 years ago) and that our population size was quite
small at one time (perhaps 10,000 breeding individuals).
To put the 0.1% genetic diversity estimate into perspective, it is useful to remember that
humans have approximately 3 billion base pairs in a haploid cell. Thus, any pair of
humans differs by approximately 3 million base pairs. These differences contain much
useful information about the evolutionary history of our species. In addition, the small
proportion of differences that occur within genes can lead to critical inferences about the
effects of natural selection. "
- deleted 9y ago[deleted]
- plaidfuji 9y agoThis is definitely true, but all of these genes have been vetted by millions of years of evolution, so we know they're rock solid. The edits we're talking about will be happening on a time scale that won't be constrained by natural selection, so by the time a weakness is found in one of these new genes, it's likely that it will already be widely adopted. I guess what I'm saying is that it's hard to anticipate what natural selection will look like when we multiply the "mutation rate" by probably > 10 orders of magnitude.
- logfromblammo 9y agoCertain breeds of dog get hip dysplasia. Dalmations go deaf. Molosser breeds often have respiratory issues, particularly pugs. This has not stopped people from breeding dogs. Natural selection will be out the window. It will be replaced entirely by intentional selection. We will certainly see new diseases rooted in human vanity and hubris, and they will become business opportunities for surgeons and pharmacists, just as our natural and lifestyle ailments have become moneymaking industries. So the great-grandchildren of people that were gifted by their parents with then-fashionable gene mutations will have all new reasons to pay for health care. And Sylvester McMonkey McBean simply unveils his star-off machine.
- D-Coder 9y ago"...all of these genes have been vetted by millions of years of evolution, so we know they're rock solid." You haven't talked with my knees recently, have you.
- eli_gottlieb 9y ago>This is definitely true, but all of these genes have been vetted by millions of years of evolution, so we know they're rock solid. Evolution does not vet for anything except population-level viability. Once upon a time, our population bottlenecked. The return of large-scale genetic diversity is normal for an animal species, especially one that has spread to practically every environment on the planet. Also, evolution is not a prescriptive standard. Oy.
- SophosQ 9y agoOur genetic homogeneity implies that anatomically modern humans arose relatively recently (perhaps 200,000 years ago) and that our population size was quite small at one time (perhaps 10,000 breeding individuals). -Another strongly supported hypothesis is that there was an near-extinction event that wiped out all but a pocket of human settlements from which we descended. - The diversity in other species that are about as old as ours is significantly far greater than ours suggesting that it is more likely an event like an unusually strong ice-age period that could've worsened our genetic diversity.
- freeflight 9y agoThat sounds really interesting, does this hypothesis have a name so I can read up on it a bit more?
- dotancohen 9y agoI'm not the OP, but the Toba catastrophe comes to mind. There were a few others.
- SophosQ 9y agoAs for what might explain the near-extinction humanity apparently once experienced, perhaps another kind of catastrophe, such as disease, hit the species. It may also be possible that such a disaster never happened in the first place — genetic research suggests modern humans descend from a single population of a few thousand survivors of a calamity, but another possible explanation is that modern humans descend from a few groups that left Africa at different times. -It's unlikely that the Toba catastrophe was the root cause of the bottleneck as reasoned in this investigation: https://www.livescience.com/29130-toba-supervolcano-effects.html https://www.livescience.com/29130-toba-supervolcano-effects.... - I wonder if the hypothesis of leaving Africa in small groups could be effectively tested.
- Xeoncross 9y ago0.1% difference is huge when talking about a ~6 billion character code. The OP is talking about the danger of moving to only a 0.001% difference (600M vs 6M).
- Danihan 9y agoThat 0.1% is obviously enough to make a pretty huge difference when some people have 140 IQ and some have a 70 IQ.