Genome of the Tyrolean Iceman reveals unusually high Anatolian farmer ancestry | Hacker News Reader

Genome of the Tyrolean Iceman reveals unusually high Anatolian farmer ancestry

sciencedirect.com

49 pointsPetiver31 comments

I'm sceptical of those SNPs linked with baldness etc. SNPs don't cause phenotypes, they're associated with them.

The guy has been dead for ~5000 years, but they're looking at SNPs linked with these phenotypes today; surely over 5000 years not all of those associations remain.

Sure, but on the other hand, he was bald.

I would consider that a strong indication at least that the authors aren't talking completely out their asses.

5000 years at 50y/human is only 100 lifetimes back. That really isn't that far.

More like 250 generations though.

I wonder if that is long enough to significantly impact LD structure.

SNPs are causal in that they can be thought of as perturbations of genes that occur prior to the genesis of the phenotype.

I think what you might be trying to say is (1) the presence of a SNP may not be sufficient for the occurrence of a phenotype, or (2) another SNP in high LD may be the true causal SNP.

Genetics is remarkably lax about correlation != causation, maybe because they can't do experiments. This leads online amateurs to have a lot of overly confident opinions they got from eg twin studies, which are not nearly as reliable as they think.

Imagine the kind of inaccurate results you'd get by comparing two versions of your code with GWAS instead of reading the commit history.

Genetics does experiments all the time, and many of them are geared towards understanding causality.

Knock-Out studies are all about determining the consequences of a genome change.

They are probably talking about population genetics, which doesn't really allow for experiments

Of course it does. You can breed up thousands of flies in a few weeks or millions of yeast in a few days and validate all sorts of theory with your experimental design.

Can't do it to humans though.

Surprised they were able to extract reliable information. I remember reading after it was finally returned to Italy body has been badly damaged and polymerized (“plastified”) by a careless attempt at preservation in Austria.

Even to the modern day, there's a decent sized Anatolian genetic influence in Austria - mostly down to the Ottoman war, and deserting and/or raping janissaries. Case in point, me - I have an anatolian ancestor (unknown) from the late 17th century on that side of my family.

You may be right about rapes as cause of gene mixing in Austria but Janissaries were not Turkish so we’re not originally from Anatolia. They consisted of boys enslaved from mostly Eastern Europe https://en.m.wikipedia.org/wiki/Janissary#:~:text=Janissarie.... They were the elite corps so the Ottoman army consisted of many other troops who did come from Anatolia.

The Ottomans were also not originally from Anatolia ...

Do you mean Turkish speakers? It is true the Turkish is part of a group of languages from Central Asia that would not have been present in Anatolia 5000 years ago.

Right. However those boys typically had Anatolian ancestry for the same aforementioned reasons - mine appears to have come via west Africa, and for a kid who’s neither us nor them, being a slave mercenary is a decent alternative.

aren't Sardinians quite pale?

Compared to whom? To people from Sicily and Calabria, maybe. To Northern Europeans or even Northern Italians, no way.

Paler than me. and I am of Irish/French ancestry. Though my French side is very 'Med'. Sardinians are paler than other Mediterranean people.

Chemicals in the diet and environment along with other environmental phenomena can switch genes on and off (gene expression) which can alter peoples appearance and habits.

Vit D is one such example of gene expression. "The actions of the vitamin D hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are mediated by the vitamin D receptor (VDR), a ligand-activated transcription factor that functions to control gene expression" [1]

So with this in mind, and knowing there are bacteria that will pretty much survive in any environment, consuming minerals which reduces availability for human consumption, how much of a humans characteristics are controlled by diet and the environment?

I would say alot. For example here in the UK, over the last 50 years, I have witnessed the reduction of dense muscle and fat in Caucasians, which in extreme will make it impossible to swim as they sink, a phenomena still seen in Black people today. [2]

Our diets are changing, and due to global food companies, food store standardisation, seed companies, agrichemical and govt legislation, people have changed quite considerably in the western world over the last 100 years, simply from the change in their diet!

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879406 [2] https://pubmed.ncbi.nlm.nih.gov/28561485/

You’ve seen people get less fat in the past 50 years?

> reduction of dense muscle and fat reduction of dense muscle and --->increased<-- fat

Interesting. I get what you mean, but I think it might be confirmation bias. My Sardinian friends are not very dark, but I would not say they are lighter than an Irish person would. They look Mediterranean through and through, but not very dark.

I wonder if anemia and thalassemia can explain a lighter skin tone, which is very common in Sardinia AFAIK.

I just see them as pale skinned people with black hair. It's a characteristic look you see.

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