Talk:Scandinavian Hunter-Gatherer

Original research -- physical appearance

In keeping with the persistent misinformation on blond hair and the evolution of ancient people, I find myself starting yet another talk page discussion to describe numerous unverifiable WP:OR statements in the article.

The breakdown of the "physical appearance" section:

"Genomic data has shown that SHGs displayed higher levels of light pigmentation variants compared to their two source populations, WHGs and EHGs."

No reference in the wiki article says this, specifically.

"SHGs had high levels of derived allele frequencies for three pigmentation-associated SNPs (SLC24A5, SLC45A2, which are associated with skin depigmentation, and OCA2/HERC2, which is associated with eye pigmentation and may contribute to a light or blonde hair colour)."

The suggestion that OCA2/HERC2 is related to blond hair isn't in thd reference, which doesn't contain the word "blond".

"A study by Günther et al, 2018, attributed this depigmentation to adaptations to cold and low light conditions.The earliest recorded individual with a combination of a blonde hair colour and a blue eye colour is a SHG from Motala."

See above. I see nothing to indicate here that the earliest blue eyed/blond individual known is an SHG. I also see nothing of Günther's proposal.

"These traits have also been found in individuals from later SHG populations like the Pitted Ware culture."

More nonsense. The study does not mention these traits. Hunan201p (talk) 22:04, 30 June 2021 (UTC)

Note, of the Günther et al (2018) proposal:

"In addition to performing this genome-wide scan, we studied the allele frequencies in three pigmentation genes (SLC24A5, SLC45A2, which have a strong effect on skin pigmentation, and OCA2/HERC2, which has a strong effect on eye pigmentation) in which the derived alleles are virtually fixed in northern Europeans today. The differences in allele frequencies of those three loci are among the highest between human populations, suggesting that selection was driving the differences in eye color, skin, and hair pigmentation as part of the adaptation to different environments [50–53]. All of the depigmentation variants at these three genes are in high frequency in SHGs in contrast to both WHGs and EHGs (Fig 4B)"

"The genomic data further allowed us to study the physical appearance of SHGs (S8 Text); for instance, they show a combination of eye color varying from blue to light brown and light skin pigmentation. This is strikingly different from the WHGs—who have been suggested to have the specific combination of blue eyes and dark skin [18,20,21,23] and EHGs—who have been suggested to be brown-eyed and light-skinned [19,20]."

Again, nothing here linking any of the three genes to blond hair, and it's selection to "different" environments rather than specific temperatures. Hunan201p (talk) 22:16, 30 June 2021 (UTC)

To add a third comment, see this supplementary materials document.

Quoting:

"The SHG group includes the seven individuals from this study, the six Motala hunter-gatherers [2], and the Neolithic Ajvide 58 hunter-gatherer [29]. From SHGs sequenced in this study, we obtained an eye and hair pigmentation portrait for SF9, Hum2, SBj and SF12. No pigmentation predictions were generated for the SF11, Hum1 and Steigen samples, due to missing data at the relevant positions. Out of the four individuals with a Hirisplex prediction, both light and dark pigmentation phenotypes were observed. SBj and SF12 exhibited high probabilities of being blue-eyed (0.91 and 0.88, respectively), while SF9 and Hum2 were predicted to have been brown eyed. The high-coverage and high quality genome of SF12 carried two copies of the h-1 haplotype (defined by the homozygous state of all h-1 haplotype SNPs, S1 Table). SF12 and Hum2 likely had dark hair (p=0.75 and p=0.99), while SF9 and SBj had light hair (p=0.58 and p=0.90). SBj presented slightly higher probabilities of being blond (0.52) than having black, brown or red hair."

"The common feature of the skin-pigmentation SNPs among these Scandinavian hunter-gatherers was a mix of light and dark skin alleles at either rs16891982 or rs1426654 (S1 Table). The Hum2 individual exhibited only derived haplotype-associated alleles at the 16 C11-defining positions, suggesting that Hum2 had at least one copy of this haplotype. SF9 and Steigen present derived variants at 8 and 13 out of the 16 screened positions, respectively. Even though both Steigen and SF9 lacked information for the core SNP rs1426654, Steigen only carried C11-associated alleles at rs1834640, rs2675345, rs938505 positions, and SF9 at rs1834640 and rs938505, which distinguish C11 from other SLC24A5 haplotypes. SF12 exhibits a different haplotype, C9, compared to the other SHGs, and carries the ancestral allele at the core SNP rs1426654, indicating dark skin pigmentation."

"A Hirisplex eye and hair color prediction was obtained for the six hunter-gatherers from Motala [2,3]. Interestingly, all individuals exhibited high probabilities of being blue-eyed (0.71-0.92). The Motala2, Motala3, Motala4 and Motala12 individuals most likely had a dark hair color (0.70-0.99), while Motala1 and Motala6 had a light shaded hair (~0.91); they may have been blond (~0.60). Similar to SF9, SF11, SF12, SBj, Hum1, Hum2 and Steigen, the Motala hunter-gatherers presented a combination of light and dark skin pigmentation alleles. Only Motala2 presented exclusively light-skin variants at both rs16891982 and rs1426654. Motala12 exhibited only haplotype-defining derived alleles at both the h-1 and the C11 associated positions. The combination of C11-associated alleles at the rs1834640 and rs2675345 SNPs with a light-pigmentation allele at the core SNP rs1426654, suggest that Motala2 and Motala4 individuals carried the C11 haplotype as well."

"The Neolithic Ajvide 58 and 70 individuals from a Pitted Ware Culture context shares part of its phenotypic variation with SHGs. While they presented high probabilities of being blue-eyed (0.79 and 0.86) and having a dark hair color (0.94 and 0.97), Ajv58 exhibits the dark skin pigmentation alleles at rs16891982 and rs1426654 positions, while Ajv70 is heterozygous at those positions.."

"Interestingly, the eye and light skin pigmentation phenotypes observed in all SHGs could potentially be explained by admixture between WHG and EHG groups. The high relative-frequency of the blue-eye color allele in SHGs, resembles WHG, while the intermediate frequencies of the skin color determining SNPs in SHGs seem more likely to have come from EHG, since both light-pigmented alleles are virtually absent from WHG."

Hence, the evidence for blond hair (and especially blond hair + blue eye combinations) among the SHG appears to be quite underwhelming in this study. Even the skin pigmentation prediction is only patially lightened in the Motala sample, and both of the Pitted Ware samples were dark haired; only one of them was light skinned. The question remains, why does this subject attract so much misinformation? Hunan201p (talk) 23:58, 30 June 2021 (UTC)

References

Re; Pigmentation compared to source populations

These are direct quotes from Torsten Günther et al (2018) and can be found in the author summary and in figure 4

"We demonstrate that Mesolithic Scandinavians had higher levels of light pigmentation variants compared to the respective source populations of the migrations, suggesting adaptation to low light levels and a surprising signal of genetic continuity in TMEM131, a gene that may be involved in long-term adaptation to the cold"

"All of the depigmentation variants at these three genes are in high frequency in SHGs in contrast to both WHGs and EHGs (Fig 4B). We conduct neutral simulations of the allele frequencies in an admixed SHG population to estimate p-values for observing these allele frequencies without selection (S9 Text). The p-values for all three SNPs are lower than 0.2; the combined p-value [54] for all three pigmentation SNPs is 0.028. Therefore, the unique configuration of the SHGs is not fully explained by the fact that SHGs are a mixture of EHGs and WHGs, but could rather be explained by a continued increase of the allele frequencies after the admixture event, likely caused by adaptation to high-latitude environments [50,52]."

I can't see any good reason to exclude this from the article. — Preceding unsigned comment added by ScoobyTrips (talk • contribs) 14:56, 10 July 2021 (UTC)

SLC24A5 and SLC45A2 Among Scandinavian Hunter Gatherers

Wikipedia: "Most of the Motala SHGs were found to have the depigmentation alleles SLC45A2 and SLC24A5.[7]"

No.

The reference given for this statement [7] is Mathieson 2015, which is "Mathieson, Iain (November 23, 2015). "Genome-wide patterns of selection in 230 ancient Eurasians".

This is what the article actually says:

"The second strongest signal in our analysis is at the derived allele of rs16891982 in SLC45A2, which contributes to light skin pigmentation and is almost fixed in present-day Europeans but occurred at much lower frequency in ancient populations. In contrast, the derived allele of SLC24A5 that is the other major determinant of light skin pigmentation in modern Europe appears fixed in the Anatolian Neolithic, suggesting that its rapid increase in frequency to around 0.9 in Early Neolithic Europe was mostly due to migration (Extended Data Fig. 4)."

In other words, the 90% prevalence among the population of 2 derived alleles or homozygosity on gene SLC24A5 only came in with the expansion of the Early European Farmers of the Neolithic around 6,000 BC. It wasn't there in the Paleolithic or Mesolithic. Also, today's homozygosity for derived alleles knocking out skin pigmentation for gene SLC45A2 didn't come in until the migration of the Yamna pastoralists from the Pontic Steppes of Russia at the start of the Bronze Age. Today's 100% homozygosity for derived alleles on both SLC24A5 and SLC45A2 didn't occur until some time after the start of the Bronze Age, around 2,000 BC.

Light skin pigmentation among modern Europeans is the result of near 100% presence of homozygosity for derived alleles on both SLC24A5 and SLC45A2. That clearly didn't exist among the Scandinavian Hunter Gatherers, as there are higher levels of SLC45A2 although not as high as the Yamna, and absence of SLC24A5, which 100% prevalence is connected to the expansion of the Early European Farmers of the Neolithic. Prof. dr. Johannes Krause and colleagues (Reich, Paabo, etc.) reasonably presume that this modern combination happened some time after the rise of the Yamna of the Bronze Age (about 4,000 years BP). https://www.youtube.com/watch?v=JTY9K1Q_Sbg&t=1165s 2001:1C00:1E31:5F00:F518:65ED:580D:1E2 (talk) 02:51, 16 October 2022 (UTC)

Also here:

Wikipedia: "In a genetic study published in Nature Communications in January 2018, the remains of an SHG female at Motala, Sweden between 5750 BC and 5650 BC was analyzed. She was found to be carrying U5a2d and "substantial ANE ancestry". The study found that Mesolithic hunter-gatherers of the eastern Baltic also carried high frequencies of the HERC2, SLC45A2 and SLC24A5 alleles."

The reference given is "9. Mittnik 2018.", Mittnik, Alisa (January 30, 2018). "The genetic prehistory of the Baltic Sea region". Nature Communications. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5789860/#MOESM1, with Supplementary Table 6 found here. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5789860/bin/41467_2018_2825_MOESM1_ESM.pdf

This is what it shows: EHG (Eastern Hunter Gatherers) and even Baltic Mesolithic show either 0% presence or 0 coverage. Most samples are from the Neolithic and Bronze Age. There is no evidence from this data that there was anything like today's homozygosity - or even heterozygosity - for SLC24A5 and SLC45A2 among Scandinavian Hunter Gatherers, before the Neolithic. 2001:1C00:1E31:5F00:A5FE:DBDF:E0E4:6FEF (talk) 17:19, 6 November 2022 (UTC)

@ip(s): Mathieson 2015 also states: A second surprise is that, unlike closely related WHGs, the Motala samples have predominantly derived pigmentation alleles at SLC45A2 and SLC24A5. Sounds like a reasonable paraphrase, but could perhaps use some clarifications.  Tewdar  19:51, 14 December 2022 (UTC)

Also, Mittnik 2018 says: Similar to other European Mesolithic hunter-gatherers, our Baltic foragers carry a high frequency of the derived HERC2 allele which codes for light iris colour, and like SHG and EHG they already possess an increased frequency of the derived alleles for SLC45A2 and SLC24A5, coding for lighter skin colour. Perhaps this could also be reworded slightly, but original interpretation of supplementary table data is probably not the best way to proceed here...  Tewdar  20:01, 14 December 2022 (UTC)

"Perhaps this could also be reworded slightly, but original interpretation of supplementary table data is probably not the best way to proceed here..." First, it's not original interpretation to point out that the statement given directly contradicts the text. Secondly, this is what they say exactly: "Similar to other European Mesolithic hunter-gatherers, our Baltic foragers carry a high frequency of the derived HERC2 allele which codes for light iris colour, and like SHG and EHG they already possess an increased frequency of the derived alleles for SLC45A2 and SLC24A5, coding for lighter skin colour (Supplementary Table 6)." (Homozygosity for the mutation on HERC2/OCA2 specifically codes for blue eyes.) Increased frequency does not equate to today's 90% prevalence of 2 derived alleles (homozygosity) on SLC24A45 that came in with the Neolithic Early European Farmers (hence a slightly elevated presence in late Mesolithic Hunter Gatherers), or the 90% prevalence of SLC45A2 that came in with the Bronze Age. Current European skin tone is the result of near 100% prevalence of homozygosity for both SLC24A5 AND SLC45A2. See prof. dr. Johannes Krause. (The blue line is SLC24A5, the green line is SLC45A2.). 2001:1C00:1E20:D900:F1B7:A520:8DE:C0CF (talk) 07:40, 4 February 2023 (UTC)

Increased frequency does not equate to today's 90% prevalence of 2 derived alleles (homozygosity) on SLC24A45 that came in with the Neolithic Early European Farmers - nobody suggested that or added that to the article, did they?  Tewdar  09:31, 4 February 2023 (UTC)

The problem is that 1) the average reader doesn't know or appreciate the difference and 2) the reconstructions don't help. I remember arguing with one individual on Quora who supported the idea that Nordic looking Scandinavian Hunter Gatherers swept down from the frozen north to drive out the swarthy Western Hunter Gatherers. :) Point is that it isn't even clear from the data that there was even heterozygosity for either SLC24A5 (or SLC45A2), until the Neolithic Early European Farmers came in, around 6,000 BC. 2001:1C00:1E20:D900:C807:11E3:C4AF:BF9F (talk) 12:21, 12 February 2023 (UTC)

The problem is that 1) the average reader doesn't know or appreciate the difference Oh. Well, perhaps you should have led with that. 😁 Maybe we could add more details from the supplementary data to clarify? I don't think the current text misrepresents the cited articles, but I suspect that Mittnik et al. are not only talking about the 'Baltic Mesolithic' individuals when they say 'Baltic foragers'.  Tewdar  12:48, 12 February 2023 (UTC)

Mittnik: "and like SHG and EHG they already possess an increased frequency of the derived alleles for SLC45A2 and SLC24A5, coding for lighter skin colour."

According to their data, they have 1 sample from the Baltic Mesolithic, Spiginas4, and it is explicitly negative for any derived alleles on SLC24A5 (0%) or SLC45A2 (0%). And was homozygous for the blue eye gene HERC2/OCA2 - all like the other Western Hunter Gatherers of that time.

From: Supplementary Table 6: Allele information of SNPs thought to be affected by selection 2001:1C00:1E20:D900:3C52:B73D:CBEE:C49D (talk) 16:57, 4 March 2023 (UTC)

To see this 'light skinned Eastern Hunter Gatherers' idea repeated in Reuters: "Certain traits of Western European hunter-gatherers, known for blue eyes and dark skin, differed from their counterparts in Eastern Europe, who had light skin and dark eyes." (REUTERS) Genetics study lays bare Ice Age drama for humans in Europe, by Will Dunham. 2001:1C00:1E20:D900:517C:25B1:F347:1DB3 (talk) 15:24, 16 March 2023 (UTC)

And more of the same - Andrew Curry, a "journalist in Berlin" writes for Science:

"They even looked different: Genetic data suggest that before the arrival of farmers in northern Europe around 6000 B.C.E., hunter-gatherers in Western Europe had dark skin and light eyes. People in Eastern Europe and Russia, meanwhile, had light skin and dark eyes."

Source: (SCIENCE) Ancient DNA upends European prehistory

"Genes reveal striking diversity within similar ice age cultures", 1 MAR 2023, BY ANDREW CURRY. I would like to see this genetic evidence, because it certainly contradicts Prof. dr. Johannes Krause of the Max Planck Institute. 2001:1C00:1E20:D900:FCAC:A9D7:6D54:7316 (talk) 08:50, 30 April 2023 (UTC)