Chromosomal Study Proposes People Were Residing in South America as far Back as 18,000 Years Ago

Discovery of chromosomal evidence

A team of scientists affiliated with many institutions in Argentina has discovered chromosomal proof of people residing in South America as far back as 18,000 years earlier. The team has published a paper explaining their work and also discoveries on the open access site PLOS ONE.

Over the past many years, researchers have discovered evidence of people first traveling to North America from Siberia about 14,000 to 17,000 years ago, utilizing what was, after that, a land bridge to Alaska. In this recent effort, the scientists have found proof proposing that the timeline might have to be pushed back a little bit.

Instead of looking for devices or bones left by the first individuals to travel to South America– which most likely was populated by people moving south down through North America and then through Central America–, the scientists utilized a chromosomal approach.

Sample collection

The scientists gathered tissue samples from 13 people living in Argentina who were thought to be descended from old migrants to the region (members of the Q Haplogroup) instead of the New World. The scientists then studied their Y chromosomes as way to establish a timeline. The Y chromosome has the largest stretch of non-recombinant DNA and is passed down to male offspring, and due to this, it offers a history of the paternal lineage.

The researchers utilized the information from the volunteers to assist produce afresh phylogenetic trees where the sizes of the branches were proportionate to the number of single-nucleotide polymorphisms, which they note correspond to time.

They then compared the information with samples gathered from 80 other people pertaining to the Q Haplogroup, who lived in other locals, such as Eurasia, and that enabled them to make estimates concerning how long individuals in South America must have been living there for their Y chromosomes to have the features that they have today– roughly 18,000 years.

The impact of research

The scholars also discovered that their work revealed the impact on the lineage of the individuals living in the area during the Younger Dryas (the time after the last ice retreat). They finish by proposing that future work related in tracing the lineage of individuals in South America should focus on the effect of the changing environment during that period.

Read the original article on PHYS.

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