This analysis refers to the Günther at al. (2015) paper already discussed here, which tested the genomes of seven pre-Beaker Copper Age and one Middle Bronze Age individuals from El Portalon Cave, near Burgos in northeast Castile, Spain.
One remarkable finding was that the so-called ATP3 individual, who lived circa 3516–3362 BCE, belonged to Y-haplogroup R1b1a2-M269, the main lineage of the contemporaneous Yamna culture (3600-2000 BCE) at the other extremity of Europe.
ATP3 belongs to mtDNA lineage of potential Indo-European origin: K1a2b, which is found mostly in northern Europe and Iran nowadays. ATP20 is U5a1c, a lineage now found mostly around the Baltic (Germany, Poland, Lithuania). All the other maternal lineages are typical of Iberia.
Unfortunately, the paper didn't report the admixtures for ATP3 and ATP20. But I just found that Genetiker ran the admixtures for all samples and that is extremely interesting.
Most samples are predominantly Southern European (ATP17=66.7%, Matojo=64.88%, ATP7=63.4%, ATP16=62.6%, ATP9=51.8%, ATP2=46.8%), except ATP3 and ATP20 who who have considerably less (ATP3=32.47% and ATP20=33.03%) as if they had been recently hybridized and only had half of the Iberian ancestry of other samples.
Both ATP3 and ATP20 have a higher percentage of Northern European and European Hunter-Gatherer ancestry, with an combined average of 20.5% and 23% respectively. Only ATP9 has more (32%).
More fascinating is the fact that ATP4 and ATP20 are the only samples with Veddoid ancestry (i.e. Indian subcontinent, but possibly of IE origin), with a remarkable 28.14% for ATP20 and a much more moderate 3.82% fro ATP3.
Actually ATP20 (2289–2050 BCE) doesn't look very European, with 7.96% of Negroid and 7.76% Northern Amerindian ancestry in addition to its 28% of Veddoid.
ATP3 (3516–3362 BCE) stands out from other samples thanks to its high Northern Middle Eastern ancestry (31.97%) against 0% for ATP20, 11% for ATP17 and between 0% and 8% for other samples. What Genetiker calls Northern Middle Eastern is what we typically referred on this forum as Caucaso-Gedrosian admixture - the same as in the "Armenian-like admixture" in Yamna samples.
With its 32% of Caucaso-Gedrosian, 14% of Northern European ancestry, 6% of European Hunter-Gatherer and 3.8% of Veddoid, it does indeed look as if ATP3 has a bit over half of Steppe ancestry, but with a higher proportion of northern Middle Eastern and Veddoid than Yamna samples. In other words it could be descended to the pre-Indo-European Anatolian R1b-M269, the group of cattle herders that would cross the Caucasus and settle in the Pontic-Caspian Steppe. So could it be an offshoot of cattle herders that directly migrated from Anatolia to Iberia during the Neolithic period. But if so, how did his lineage not get more admixed along the way ? Neolithic farmers all over Europe were overwhelmingly (and often exclusively) Southern-European in admixture.
What baffles me the most is that this individual's ancestors managed to maintain a relatively pure West and South Asian admixture while crossing all Europe at the height of the Neolithic. Could it represent a migration of copper metallurgists from Anatolia to Iberia ? R1b tribes from the Pontic Steppe are thought to have started invading the Balkans several centuries before the Yamna period, from c. 4200 BCE. Copper metallurgy was already well implanted in the Balkans by then, but may have been brought from central Anatolia. An alternative scenario is that R1b-M269 invaders took wives with high Middle Eastern admixture in copper towns in the Balkans, and that their descendants spread metallurgy fairly quickly all the way to Iberia. If that is the case, the Southern-European component might be Balkanic rather than Iberian.
The main problem with the diffusion of copper metallurgists is that copper working is not documented in northern Spain until 3000 to 2500 BCE and this sample dates from c. 3500 BCE (see map of Copper Age diffusion).
In conclusion, it seems pretty clear from the autosomal analysis that ATP3 is ethnically different from other samples from Chalcolithic El Portalon, and is not a native inhabitant of Neolithic Iberia, but a recent Copper Age immigrant, although how he got there remains unclear. A small group (or extended family) of Steppe people with (ox-drawn) carts travelled all the way there, probably after having intermingled with Copper Age immigrants from Anatolia in the Balkans. The maternal north-east European lineage indicates that females also took part in the migration. Even though such events must have been relatively rare and were probably not representative of a large-scale PIE migration.
This could explain how early subclades of R1b-M269 (S116* and DF27) ended up in southern France and Iberia, bypassing the rest of Europe. The bulk of R1b people would only have arrived from the Balkans to Central Europe c. 2800-2500 BCE, and a second wave of R1b-S116 (probably L21) moved into Western Europe from 2500 to 2000 BCE. A third wave (U152) expanded from Central Europe during the Hallstatt and La Tène periods.
A small predominantly male population of Steppe migrants to Iberia in the Copper Age that grew progressively through a founder effect in the paternal line would explain why PIE languages didn't take hold in the peninsula until later Bronze Age migrations (Celts).
An early incursion of Steppe/Balkanic R1b-M269 people to Iberia would also elucidate the sudden appearance of copper technology in the peninsula.
Image source: "Illustration of every day life in the El Portalon cave during the Neolithic and Copper Age"
One remarkable finding was that the so-called ATP3 individual, who lived circa 3516–3362 BCE, belonged to Y-haplogroup R1b1a2-M269, the main lineage of the contemporaneous Yamna culture (3600-2000 BCE) at the other extremity of Europe.
ATP3 belongs to mtDNA lineage of potential Indo-European origin: K1a2b, which is found mostly in northern Europe and Iran nowadays. ATP20 is U5a1c, a lineage now found mostly around the Baltic (Germany, Poland, Lithuania). All the other maternal lineages are typical of Iberia.
Unfortunately, the paper didn't report the admixtures for ATP3 and ATP20. But I just found that Genetiker ran the admixtures for all samples and that is extremely interesting.
Most samples are predominantly Southern European (ATP17=66.7%, Matojo=64.88%, ATP7=63.4%, ATP16=62.6%, ATP9=51.8%, ATP2=46.8%), except ATP3 and ATP20 who who have considerably less (ATP3=32.47% and ATP20=33.03%) as if they had been recently hybridized and only had half of the Iberian ancestry of other samples.
Both ATP3 and ATP20 have a higher percentage of Northern European and European Hunter-Gatherer ancestry, with an combined average of 20.5% and 23% respectively. Only ATP9 has more (32%).
More fascinating is the fact that ATP4 and ATP20 are the only samples with Veddoid ancestry (i.e. Indian subcontinent, but possibly of IE origin), with a remarkable 28.14% for ATP20 and a much more moderate 3.82% fro ATP3.
Actually ATP20 (2289–2050 BCE) doesn't look very European, with 7.96% of Negroid and 7.76% Northern Amerindian ancestry in addition to its 28% of Veddoid.
ATP3 (3516–3362 BCE) stands out from other samples thanks to its high Northern Middle Eastern ancestry (31.97%) against 0% for ATP20, 11% for ATP17 and between 0% and 8% for other samples. What Genetiker calls Northern Middle Eastern is what we typically referred on this forum as Caucaso-Gedrosian admixture - the same as in the "Armenian-like admixture" in Yamna samples.
With its 32% of Caucaso-Gedrosian, 14% of Northern European ancestry, 6% of European Hunter-Gatherer and 3.8% of Veddoid, it does indeed look as if ATP3 has a bit over half of Steppe ancestry, but with a higher proportion of northern Middle Eastern and Veddoid than Yamna samples. In other words it could be descended to the pre-Indo-European Anatolian R1b-M269, the group of cattle herders that would cross the Caucasus and settle in the Pontic-Caspian Steppe. So could it be an offshoot of cattle herders that directly migrated from Anatolia to Iberia during the Neolithic period. But if so, how did his lineage not get more admixed along the way ? Neolithic farmers all over Europe were overwhelmingly (and often exclusively) Southern-European in admixture.
What baffles me the most is that this individual's ancestors managed to maintain a relatively pure West and South Asian admixture while crossing all Europe at the height of the Neolithic. Could it represent a migration of copper metallurgists from Anatolia to Iberia ? R1b tribes from the Pontic Steppe are thought to have started invading the Balkans several centuries before the Yamna period, from c. 4200 BCE. Copper metallurgy was already well implanted in the Balkans by then, but may have been brought from central Anatolia. An alternative scenario is that R1b-M269 invaders took wives with high Middle Eastern admixture in copper towns in the Balkans, and that their descendants spread metallurgy fairly quickly all the way to Iberia. If that is the case, the Southern-European component might be Balkanic rather than Iberian.
The main problem with the diffusion of copper metallurgists is that copper working is not documented in northern Spain until 3000 to 2500 BCE and this sample dates from c. 3500 BCE (see map of Copper Age diffusion).
In conclusion, it seems pretty clear from the autosomal analysis that ATP3 is ethnically different from other samples from Chalcolithic El Portalon, and is not a native inhabitant of Neolithic Iberia, but a recent Copper Age immigrant, although how he got there remains unclear. A small group (or extended family) of Steppe people with (ox-drawn) carts travelled all the way there, probably after having intermingled with Copper Age immigrants from Anatolia in the Balkans. The maternal north-east European lineage indicates that females also took part in the migration. Even though such events must have been relatively rare and were probably not representative of a large-scale PIE migration.
This could explain how early subclades of R1b-M269 (S116* and DF27) ended up in southern France and Iberia, bypassing the rest of Europe. The bulk of R1b people would only have arrived from the Balkans to Central Europe c. 2800-2500 BCE, and a second wave of R1b-S116 (probably L21) moved into Western Europe from 2500 to 2000 BCE. A third wave (U152) expanded from Central Europe during the Hallstatt and La Tène periods.
A small predominantly male population of Steppe migrants to Iberia in the Copper Age that grew progressively through a founder effect in the paternal line would explain why PIE languages didn't take hold in the peninsula until later Bronze Age migrations (Celts).
An early incursion of Steppe/Balkanic R1b-M269 people to Iberia would also elucidate the sudden appearance of copper technology in the peninsula.
Image source: "Illustration of every day life in the El Portalon cave during the Neolithic and Copper Age"
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