A breakthrough paleogenomic study published in Nature Ecology & Evolution has sequenced the DNA of 11,000-year-old human remains found in the Talamanca Range of Costa Rica. The research identifies a previously unknown lineage of Pleistocene foragers who developed specialized genetic adaptations to the unique environmental stressors of high-altitude tropical cloud forests. Researchers discovered specific selection in the HLA-DRB1 gene complex, which provided early resistance to endemic fungal pathogens unique to humid, high-elevation ecosystems.
The study also highlights a metabolic shift linked to the consumption of high-tannin flora found in the pre-Columbian tropics. This finding suggests that human populations in the Americas were diversifying and adapting to specialized micro-climates much earlier than previously thought, challenging the model of a uniform southward migration. The data further reveals a genetic bottleneck that occurred roughly 12,500 years ago, likely coinciding with a period of rapid volcanic activity in the region.