Evaluating population histories in Patagonia and Tierra del Fuego, Chile, using ancient mitochondrial and Y‐chromosomal DNA

Abstract

Objectives: This study aims to characterize the genetic histories of ancient hunter-gatherer groups in Fuego-Patagonia (Chile) with distinct Marine, Terrestrial, and Mixed Economy subsistence strategies. Mitochondrial (mtDNA) and Y-chromosome data were generated to test three hypotheses. H 0 : All individuals were drawn from the same panmictic population; H 1 : Terrestrial groups first populated the region and gave rise to highly specialized Marine groups by $7,500 cal BP; or H 2 : Marine and Terrestrial groups represent distinct ancestral lineages who migrated independently into the region. Methods: Ancient DNA was extracted from the teeth of 50 Fuegian-Patagonian individuals dating from 6,895 cal BP to after European arrival, and analyzed alongside other individuals from previous studies. Individuals were assigned to Marine, Terrestrial, and Mixed Economy groups based on archeological context and stable isotope diet inferences, and mtDNA (HVR1/2) and Y-chromosome variation was analyzed.

Tales from the end of the world: three decades of paleogenetic research in Patagonia

“…In addition, the identification of these lineages has been possible only after a significant increase in the sample size and geographical coverage. The overall low uniparental genetic diversity [63,[72][73][74]76,78,99], together with the reported excess of short Runs of Homozygosity [75] and the low conditional heterozygosity [76] from genome-wide data, support a reduced effective population size. This scenario is compatible with the founder effect(s) during the peopling of the region, followed by isolation and persistent small group sizes.…”

“…Ancient DNA studies of Y-chromosome have been carried out since the early stages of genetic research in the region [72][73][74], focusing on Short Tandem Repeats (STR) and the C to T transition at the DYS199 locus as a diagnostic polymorphism of Q-M3 haplogroup (also known as Q1b1a1a (ISOGG 2019)), a widespread lineage across the Americas. In all individuals from Patagonia yielding positive results, the lineage Q-M3 has been characterised.…”

“…4,700 years BP [70] and site Bahí a Buena dated to ca. 6,700 years BP [74], each with a single individual. Towards the Late Holocene haplogroup B2 is found at a frequency of 31% in Salitroso Lake basin [81,82] as well as in other areas of continental southern Patagonia (but with no peer-reviewed publication for those [83,84]).…”

Ecogeography‐related humerus morphological variation within southern Patagonia hunter‐gatherers

“…This lower genetic diversity could be the result of migration histories, adaptation to the environment, founder effects and/or other forms of genetic drift (Crespo et al, 2018; de la Fuente et al, 2015). In this context, recent mitochondrial DNA and Y‐chromosome results show that hunter‐gatherers represent distinct lineages that diverged before the ancestors of marine and terrestrial hunter‐gatherers migrated into SP (Balentine et al, 2023). Other genome‐wide DNA studies identified patterns that pointed to the earliest marine groups as being descendants of terrestrial groups (Nakatsuka et al, 2020).…”

“…Other genome‐wide DNA studies identified patterns that pointed to the earliest marine groups as being descendants of terrestrial groups (Nakatsuka et al, 2020). Genetic structure for Late Holocene SP populations identifies separated clusters for the ecogeographical regions (Balentine et al, 2023; Crespo et al, 2018; Nakatsuka et al, 2020). However, a cline was also presented ranging from SGB at one end to the people who inhabited western archipelagos at the other, a cline that is more noticeable in individuals from MP, in a middle point between NIG and BC individuals (Nakatsuka et al, 2020).…”