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Landmark ancient-genome study shows surprise acceleration of human evolution

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Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#91

Post by scotty79 »

beloch wrote: post #64
MrBuddyCasino wrote: post #60

Earlier quoted context omitted.

But the DNA of the sumatran tiger and a Siberian tiger is also over 99% identical?

The DNA of humans and chimps is 98.8% identical. The percent difference between genomes of species is one of those tricky measures that doesn't really give good intuition. I find it much more useful to think in terms of the time since two species shared a common ancestor. e.g. For humans and chimps, that's several million years. For Sumatran and Siberian tigers, it's around a hundred thousand years.

What percentage of DNA do all mammals share? And what all mammals except platypus?

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#92

Post by ralfd »

samsartor wrote: post #65
like_any_other wrote: post #7

Is there any species, other than humans, that is found all across the globe (i.e. geographically separated), and has not differentiated into subspecies? Wolves, elephants, tigers, bears, and foxes have all been categorized into multiple subspecies each, distinct but able to interbreed.

My understanding is that humans have very limited genetic diversity compared to most other animals, because of the population bottlenecks we've been through. And further, that diversity is mostly between individuals, not between groups. The distinction is easy to see in cats vs dogs: they both have similar overall genetic diversity but two Chihuahuas have virtually all the same genes (the small angry ones) while two…

> The average european person and the average east asian person are a little bit different genetically, but way less different than any two real europeans or two east-asians are to one another.

This is always touted as an “racism-is-not-only-immoral-it-is-scientifically-wrong” argument, but it is a fallacy.

Example: The average height (a trait with very high heritability) of Dutch men is 6’0 feet (183 cm) and the average height of Philippine men is 5’4 (163 cm). This means the height difference between these two groups is 20 cm. And it is obvious that the difference inside one group MUST be larger, for example there are 6’4 Dutch basketballers but also certainly Dutch 5’2 horse riding jockeys.

And depending on context both of these insights are useful. For example if you manage a basketball team it is much more effective to consider people as individuals, simplified you should hire very tall people (regardless if they are Dutch or Philippines) who can throw precisely a ball into a basket. But the diversity between population groups points to real information too! If you sell shoes to both countries you shouldn’t provide the same one-size-fits-all and assume to catch the same percentage of the market.

Plus the overlap in one metric is expanding into separable clusters the more dimensions are used:

https://i.sstatic.net/r6cWd.jpg

Take a Dutch and Philippine who have the exact same height: Their own respective brothers (heck, even twins) will not be the same perfect match, instead being a bit taller or smaller. But the more variables you consider (weight, muscle composition, leg length, head radius, hand size, form of earlobe .. etc) you will find that holistically seen two brothers truly are much more similar to each other than to a stranger.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#93

Post by like_any_other »

orsorna wrote: post #53
like_any_other wrote: post #21

Earlier quoted context omitted.

> people who would kill others over physiological differences Most of them just want to enforce borders. And then the dogma that we are all the same is co-opted by people who would see their ethnic group wiped out, as they are told that they don't even exist except as a meaningless social construct, and their desire for ethnic self-preservation is therefore illegitimate - there is nothing to preserve! The same rhetor…

>And then the dogma that we are all the same is co-opted by people who would see their ethnic group wiped out Are you referring to certain people? People sympathetic to Palestinians? I mean yeah obviously it's wrong to preach equity for me but not for thee, but I'm not really going to get into a pissing match about Israel/Palestine, sorry, because that's deflection from my point. So there are two choices here: 1) All…

Nobody talks about "performance metrics" when distinguishing between Sumatran and Siberian tigers. What happens instead is humans try to preserve their populations and distinctions. "It's all the same" is corrosive to preservation.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#94

Post by naasking »

bluebarbet wrote: post #89
John7878781 wrote: post #58

Earlier quoted context omitted.

> Two bird populations living in the same locale but divided by a mountain range therefore not naturally breeding with each other would classify as a different species, even if they could breed with each other. Really? I thought the requirements for species classification were: (1) must be able to reproduce and (2) offspring must be fertile. Is it less objective than that?

Thought experiment. Three populations, A, B, and C, divided geographically along a line. Individuals from group A can breed successfully with those from B but not with those from C. Individuals from group C can breed successfully with those from B but not A. How many species are there? This is why the term "species" can never be entirely objective. I remember the eureka moment I had when I finally understood this (ad…

It can even be more subtle, it's entirely possible that some rare members of A can C breed, and some members of C and B would not be able to breed. The "fertility" relation can only be decided between two individuals, not groups. Group-level fertility is a statistical average of individual fertility.

That said, I don't think that means that "species" is entirely subjective or meaningless.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#95

Post by ralfd »

zozbot234 wrote: post #86
Mikhail_K wrote: post #77

From the article: We finally observed signals of selection for combinations of alleles that today are associated with three correlated behavioural traits: scores on intelligence tests (increasing 0.74±0.12), household income (increasing 1.12±0.12) and years of schooling (increasing 0.63±0.13). These signals are all highly polygenic, and we have to drop 449–1,056 loci for the signals to become non-significant(Extended…

> That's the part that the speech police is afraid of. Why? This article just focuses on changes in West Eurasia (probably because that's what they had data for), but the bulk of changes that resulted in behavioral modernity surely occurred in Africa - where the genetic variability for them to occur was and still is far greater than elsewhere - and plausibly similar changes occurred in other regions such as Central E…

> and plausibly similar changes occurred in other regions

Sure. But did ALL regions change? And did they change to the same destination? When the environments differed so much? It is easy to see how answers (or the questions themselves) could be politically contentious.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#96

Post by naasking »

krapp wrote: post #47
IncreasePosts wrote: post #40

Earlier quoted context omitted.

Do humans not fit the standards for being broken into multiple subspecies? I assumed that they would but "the science community" is too scared of the implications when idiots learn about it. I look at a sumatran tiger and a Siberian tiger and I see a lot less variance than I see when I look at a pygmy, a Norwegian, an sentinel islander, and a han Chinese person

>Do humans not fit the standards for being broken into multiple subspecies? No. Multiple human subspecies did once exist (examples being Neanderthals, Denisovans, Homo Erectus, and Homo Floresiensis) but only our species, Homo Sapiens, remains (with traces of Neanderthal DNA so there was some interbreeding.) However race is a cultural and social construct. Different human races are not different human subspecies. A P…

> However race is a cultural and social construct. [...] The superficial variations in average height, skin color, etc. do not vary enough to constitute species differentiation

Species is also a social construct. Calling race a social construct isn't the persuasive argument people seem to assume.

> the vast majority of genetic variation exists within populations (in other words, within "races") and not between them.

This is is a fallacious argument, because there is no such thing as the "average Norwegian" and the "average Pygmy", and so you cannot even construct a meaningful sentence like "the average Norwegian and the average Pygmy are more alike than any individual Norwegian is to any other Norwegian". People need to stop using this silly argument.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#97

Post by naasking »

AlotOfReading wrote: post #6
A_D_E_P_T wrote: post #2

Not that surprising when you consider, as the paper does, the explosion of very meaningful traits such as the ability to digest lactose and various anti-malaria adaptations e.g. Sickle Cell and the Duffy-null mutation. It's just controversial for obvious reasons. The notion that human groups may have meaningfully evolved in different ways over the past 10,000 years, and may still be evolving, is an unpopular one on b…

The reason no one wants to talk is that these discussions are always co-opted by racists wanting to affirm their beliefs, regardless of the underlying science. Reich in particular is borderline deliberate about attracting those sorts with his lab's research, because of how badly he chooses to handle the topic and terminology of race.

> The reason no one wants to talk is that these discussions are always co-opted by racists wanting to affirm their beliefs

So? People need to stop undermining science and openly sharing information because some people have bad ideas.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#98

Post by throwup238 »

like_any_other wrote: post #7

Is there any species, other than humans, that is found all across the globe (i.e. geographically separated), and has not differentiated into subspecies? Wolves, elephants, tigers, bears, and foxes have all been categorized into multiple subspecies each, distinct but able to interbreed.

Many researchers now refer to neanderthals as Homo sapiens neanderthalensis, a subspecies of modern humans.

It doesn’t get talked about much because it’s a sideshow without an easy resolution, but the question of modern and archaic human speciation is far from a settled problem and many of the species formerly considered to be separate are now often lumped in as subspecies.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#99

Post by zozbot234 »

iknowimarat wrote: post #81
MrBuddyCasino wrote: post #79

Earlier quoted context omitted.

I don’t think the out-of-africa hypothesis is defensible in light of recent archeological findings, and, incidentally, DNA complexity analysis.

Out of africa remains defensible but more and more people will come to the conclusion that the chinese hyporhesis of the multiregional origin is somewhat true so we will get a hybrid i guess

The problem is that "Out of Africa" is an uninformative name. The outflow from Africa was well underway 100k years ago or even 200k years ago, and there was no inherent break between that ongoing outflow and what happened 40k years ago when (inasmuch as we can reconstruct today) behaviorally modern rather than 'archaic' humans began to migrate out, which we now call "Out of Africa". So it's hard to even tell apart the "recent Out of Africa" and the "multiregional" hypotheses in a way that might help settle a debate.

Re: Landmark ancient-genome study shows surprise acceleration of human evolution

#100

Post by timmg »

AlotOfReading wrote: post #29
MontyCarloHall wrote: post #26

Earlier quoted context omitted.

>Reich in particular is borderline deliberate about attracting those sorts with his lab's research, because of how badly he chooses to handle the topic and terminology of race. Sorry, do you have any examples? His views that I've read [0, 1] are scientifically rigorous and terminologically precise, deftly navigating the politics that some consider extremely controversial. To wit, one of my favorite passages from [1],…

It's unfortunate that the URL happens to be buzzfeed, but there was an open letter to Reich by other academics about his terminology in the book you're quoting [0]. The short of it is that social categorizations we believe in like race intersect with genetics in a very complicated way. Reich is a world-class expert in genetics. He simply commits the same error as many other other experts in discounting the complexity…

Not the person you were replying to, but: did you read that letter?

It is horribly argued. It's mostly poor analogies and non-sequiturs. It's no wonder Buzzfeed was the only place they could get to publish it.

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