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Aboriginal Australian genomes reveal Indian ancestry (2013)

nature.com

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Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#121

Post by dragonwriter »

Zurrrrr wrote: post #42
ajross wrote: post #40

Earlier quoted context omitted.

> emotionally charged subject, which is unfortunate [...] The simplified and (generally) commonly accepted narrative [...] that potentially complicates a lot of the cultural positioning. [...] it's a shame Uh... what's a shame? None of that stuff happened. You've picked a fight with a strawman here. No one is engaging like that with the linked article, or here in the HN thread, except you.

He's talking about the fact that Aboriginals, not unlike Native Americans, reject any attempt to explain their origin via science as they stick to the story of their origin that comes from their religion, and see the science based origin as disrespectful.

> Aboriginals, not unlike Native Americans, reject any attempt to explain their origin via science as they stick to the story of their origin that comes from their religion, and see the science based origin as disrespectful.

I mean, if we are going to make these kinds of broad generalizations and comparisons, could we at least change “Native Americans” to “Christian fundamentalists”.

It’s not any less true.

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#122

Post by ComposedPattern »

nhchris wrote: post #49
viewtransform wrote: post #30

More than a decade ago I submitted my DNA to the National Genographic Project [1] which was an attempt to trace ancient human migration using Y chromosome and mitochondrial DNA from a sampling of people around the world. My paternal Y-chromosome line showed an ancient mutation (>50K year ago) carried by humans who had likely spread through a coastal migration from Africa around coasts of the Arabian Sea down to South…

> As we gather more data our understanding of human migration inevitably clashes with identity politics/nationalism and previous simplistic pre-scientific classifications based on skin color and facial features Does it? Because most studies find that people living in the same country are indeed more closely related to each other than to people of different countries, roughly according to what you would expect from ge…

> https://commons.wikimedia.org/wiki/File:Individual-level_hum...

Here's the same image in black and white: https://i.imgur.com/x2QzHgB.png. Do you see five clear clusters? I only found four: https://imgur.com/AFj2GWG.png.

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#123

Post by ImaCake »

Jedd wrote: post #98
ImaCake wrote: post #61

Earlier quoted context omitted.

> the original population was partly / mostly replaced Thats not what this data shows. What it does show is that some migrants from india joined the existing culture and left a genetic, and presumably, cultural mark. When a smaller population mixes genetically with a larger population they effectively add a small amount of novel genetic markers to the population in what we call introgression.

You're right. I should have chosen better phrasing - perhaps gene pool instead of population, and diluted (but that still seems awkward) rather than replaced. Is an 11% genetic incursion a lot for ~ 150 generations? I don't know, TFA doesn't hint, and I suspect we don't have an abundance of natural experiments to compare with.

> Is an 11% genetic incursion a lot for ~ 150 generations?

I am not sure either. However, we do have a lot of natural experiments (and lab experiments) to explore this.

The 11% number comes from a clustering analysis. The user supplies k = number of ancestry groups, and the algorithm estimates proportion of genetics specific to each of k ancestry groups. So basically fancy k-means clustering. I don't know how robust it is and I would suspect a biased estimate.

As for over time... also complex. But I would imagine the best models would use exponetial distributions or similar as their basis (i.e. initially fast decrease in percentage followed by a slower rate of loss until equilibrium is reached).

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#124

Post by thoi3u4o2i34324 »

Zurrrrr wrote: post #42
ajross wrote: post #40

Earlier quoted context omitted.

> emotionally charged subject, which is unfortunate [...] The simplified and (generally) commonly accepted narrative [...] that potentially complicates a lot of the cultural positioning. [...] it's a shame Uh... what's a shame? None of that stuff happened. You've picked a fight with a strawman here. No one is engaging like that with the linked article, or here in the HN thread, except you.

He's talking about the fact that Aboriginals, not unlike Native Americans, reject any attempt to explain their origin via science as they stick to the story of their origin that comes from their religion, and see the science based origin as disrespectful.

[flagged]

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#125

Post by nhchris »

rafram wrote: post #117
nhchris wrote: post #49

Earlier quoted context omitted.

> As we gather more data our understanding of human migration inevitably clashes with identity politics/nationalism and previous simplistic pre-scientific classifications based on skin color and facial features Does it? Because most studies find that people living in the same country are indeed more closely related to each other than to people of different countries, roughly according to what you would expect from ge…

> and the simplistic categorization of humans into ~5 races corresponds well to clusters on a genetic map Are you familiar with principal component analysis? That’s what was used to generate the very clearly clustered charts that you linked to. It’s useful for analysis because it exaggerates the density and distinctness of clusters based on major features. But what that means is precisely that those clusters are not…

> it exaggerates the density and distinctness of clusters

It does the opposite - the PCA graph shown is 2D, meaning points in the N-dimensional space are projected onto a single plane. In this projection, information is lost - i.e. point-clouds that are distinct in 3D may overlap in 2D. While we are shown the axes along which the data is most distinct, the true clusters are even more distinct, as every added dimension would contribute additional 'distinctness'.

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#126

Post by boomboomsubban »

Zurrrrr wrote: post #111
tjmc wrote: post #102

Earlier quoted context omitted.

Got a source for this fact? Generalising opinions to a whole race is rarely wise. Perhaps like anyone else with religious beliefs, those who are offended simply want their culture respected.

[flagged]

>My source is growing up there

Where did you grow up that simultaneously had a large Aboriginals and Native American population?

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#127

Post by ImaCake »

nhchris wrote: post #67
ImaCake wrote: post #56

Earlier quoted context omitted.

Yes, ppl in the same country have more similar genomes. But modern population genetics has found that 1. There is more similarity than difference between any 2 humans on earth (there are africans and europeans who share more dna than with others of their own ancestry. And, 2. People move around, a lot! We knew this already but there are a huge number of undocumented migrations that are being revealed by these studies…

> there are africans and europeans who share more dna than with others of their own ancestry You're probably referring to the "greater variation within than between races" argument. But it's only true when looking at single genes, not collections of genes - that is how genetic tests can accurately determine race. And most traits are polygenic, so it does not even make sense to compare using only individual genes. Tha…

Yes you are right about the greater variation being localised. But I thought it was localised at the level of linkage disequlibrium blocks which can encompass many thousands of genes at their largest.

Regardless the genetic distance between any two people remains tiny compared to the distance between even closely related species or sub-species elsewhere.

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#128

Post by wycx »

a_bonobo wrote: post #65
coderenegade wrote: post #52

Earlier quoted context omitted.

It's the wood. You can rank woods by the amount of strain energy per unit of mass that they can take before breaking. The higher this figure, the better the bow, because it'll store more energy for a lower mass in the limbs before it breaks, and the differences can be fairly significant. The best bow woods are all at the top of this list, along with a few that should be good in theory but aren't used likely for other…

Most Australian wood is also ultra-hard, you can't have a bendy bow from there. People used to build streets from blocks of Jarrah wood [1]. A much more popular Australian weapon was the combination of spear thrower and spear; that'll take your head off clean. https://fremantlestuff.info/streets/blocks.html#:~:text=Aust... .

Including one of the hardest of them all: https://en.wikipedia.org/wiki/Allocasuarina_luehmannii

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#129

Post by nhchris »

ComposedPattern wrote: post #122
nhchris wrote: post #49

Earlier quoted context omitted.

> As we gather more data our understanding of human migration inevitably clashes with identity politics/nationalism and previous simplistic pre-scientific classifications based on skin color and facial features Does it? Because most studies find that people living in the same country are indeed more closely related to each other than to people of different countries, roughly according to what you would expect from ge…

> https://commons.wikimedia.org/wiki/File:Individual-level_hum... Here's the same image in black and white: https://i.imgur.com/x2QzHgB.png . Do you see five clear clusters? I only found four: https://imgur.com/AFj2GWG.png .

I was speaking off the top of my head, hence the ~ preceding the 5. That said, more clusters may be visible on a 3D graph. The data itself has many more dimensions, and we see only a projection.

Re: Aboriginal Australian genomes reveal Indian ancestry (2013)

#130

Post by magicalist »

nhchris wrote: post #118
magicalist wrote: post #104

Earlier quoted context omitted.

> that people living in the same country are indeed more closely related to each other than to people of different countries These charts don't show what you apparently think they do. The samples in the larger datasets (like the HGDP) are chosen for their differentiation, often from indigenous groups, with admixture samples usually removed (the first adds in a few admixture types for the specifics of their study).

If my statement wasn't true, there would be no way to distinguish admixture from indigenous in the first place.

Your statement was "people living in the same country are indeed more closely related to each other than to people of different countries"

The first chart shows a direct counterexample with "African American", "Mexican American" and "North America" groups more separated from each other than from other groups and yet many of them live in the same country. These are also not the only groups of people you'd find in North America, they're just the ones used in the study of Northwestern american indigenous groups that this is screenshotted from. This is, again, poor evidence for your claim.

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