Ancient mitogenomes of Argentine Patagonia (6070-310 YBP) reveal the early contribution of lineages not previously found in South America

Abstract

Patagonia, a cul-de-sac for the continental dispersal of Homo sapiens into the Americas, has been extensively analyzed by archaeologists and bioanthropologists. Despite its deep and rich archaeological record, the genetic make up of its pre-contact inhabitants is barely known. We present the analysis of 19 mitogenomes recovered by NGS from archaeological sites in Central Patagonia (Chubut, Argentina). 15 are pre-contact samples, (6,010-770YBP), and four are samples from historical times (550-310YBP). Preservation of the samples was extraordinary, with endogenous DNA values up to 68%. Preliminary analysis indicates that mtDNA genomes. Central Patagonia belong to haplogroups B2 (21%), C1b (21%), C1c (5%), D1 (47%) and D4h3a (5%). This is surprising when compared with a database of 19,000 control region sequences and >2,100 mitogenomes of Native American origin: 1) While modern indigenous populations from Northern and Central Patagonia of Argentina and Chile derive 41-54% of their maternal lineages from clades B2i2 and C1b13, none of these are present in our dataset; 2) 75% of our B2 and C1b lineages share derived polymorphism with lineages so far known to be present only in modern Central-Western Argentina; and 3) although modern Patagonians carry the highest continental frequencies of D1g, the ancient set is enriched mostly in D1g5, a lineage widely distributed from South-Central Andes to Tierra del Fuego (including two samples with private motifs not described before). The upcoming analysis of the nuclear portion of these samples will help us better understand migratory and admixture processes in the Patagonian region.

Uniparental origins of the admixed Argentine Patagonia

“…Although it is known that haplogroup B2 decreases in frequency southwards of South America, studies based on ancient DNA samples have reported its presence in the Patagonia region. In the central Patagonia region, Parolin, Fregel‐Lorenzo, et al (2017) found B2 at a frequency of 21% in 19 samples. Arencibia et al (2019) also documented five samples with B2 mtDNAs in the Lago Salitroso site located in the Santa Cruz Province that was dated to between 690 ± 40 and 352 ± 40 ybp.…”

“…Haplogroup B2, was reported in ancient samples dated to between ca. 3800 and 3600 ybp (Franco et al, 2017) by Moraga et al (2016), Arencibia et al (2019), Moreno‐Mayar et al (2018), and Parolin, Fregel‐Lorenzo, et al (2017). While Moreno‐Mayar et al (2018) and Parolin, Fregel‐Lorenzo, et al (2017) dismissed the presence of haplogroup B2i2 through complete mitogenome sequence, the mutation A470G, which defines B2i2, was not analyzed by Arencibia et al (2019).…”

“…3800 and 3600 ybp (Franco et al, 2017) by Moraga et al (2016), Arencibia et al (2019), Moreno‐Mayar et al (2018), and Parolin, Fregel‐Lorenzo, et al (2017). While Moreno‐Mayar et al (2018) and Parolin, Fregel‐Lorenzo, et al (2017) dismissed the presence of haplogroup B2i2 through complete mitogenome sequence, the mutation A470G, which defines B2i2, was not analyzed by Arencibia et al (2019). Although C1b13 mtDNAs have never been reported in any ancient or historical sample, many ancient studies are not resolutive enough to define this lineage.…”

Towards an ethical and legal framework in archeogenomics: A local case in the Atlantic coast of central Patagonia

“…Even though the results have not been published yet, some preliminary findings have been reported in national conferences in Argentina (Millán et al, 2021; Parolin et al, 2017; Parolin, Bravo‐López, et al, 2019; Parolin, Galimany, et al, 2019; Tamburrini et al, 2019), and formally delivered to the Undersecretariat of Culture and the communities of belonging through a formal written report and a workshop, respectively and in agreement to current ethical and legal legislation which make explicit the obligation to disseminate the results of scientific research (Table 1).…”

“…It might also provide greater security to other relevant parties, such as the Indigenous communities, regarding the treatment, status, and monitoring of their Ancestors' remains, compared with a scenario where the responsible researchers send the samples abroad, acting only as "sample providers" (Argüelles et al, 2022). Even though the results have not been published yet, some preliminary findings have been reported in national conferences in Argentina (Millán et al, 2021;Parolin et al, 2017;Parolin, Bravo-L opez, et al, 2019;Parolin, Galimany, et al, 2019;Tamburrini et al, 2019), and formally delivered to the Undersecretariat of Culture and the communities of belonging through a formal written report and a workshop, respectively and in agreement to current ethical and legal legislation which make explicit the obligation to disseminate the results of scientific research (Table 1).…”