Genome Study of 139 Indigenous Groups Reveals Humans Split Three Times in Their Journey From Africa to the Americas

Human habitation across the world was composed of many ancient treks between several continents. Researchers have identified one of these treks through an extensive genomic sequencing, according to Live Science. This trek to South America stood apart for experts because, if true, it is the 'longest human migration out of Africa' in human history. Findings regarding this analysis were published in Science.

The identified trek began in Africa, went through Asia, and ended in the southern tip of South America. As per experts, throughout this journey, three population splits took place. One of these splits led to the earliest known human settlement in Patagonia 14,500 years ago.

For the study, scientists analyzed 1,537 genomes in total, which belonged to 139 distinct ethnic groups. The genetic material was collected by the GenomeAsia 100K consortium, whose data set also included the Asian population whose ancestors participated in the earliest migrations into the Americas. Through the examination of the indigenous population's genetic background, researchers determined three time periods when the voyaging population split into groups. 

The pursuit was not easy for the organization, as many of the samples had to come from remote populations, stated South China Morning Post. "It is often very difficult to access these communities and obtain permission to conduct genetic research. Our team invested significant effort in establishing collaboration with local scientists and securing ethical approval," study co-author Hie Lim Kim, a population genomics professor at Nanyang Technological University in Singapore, shared. However, through collaborations and efforts, they created an extensive database. 

The first split happened sometime between 26,800 and 19,300 years ago, amidst the Last Glacial Maximum period. The indigenous population split from the North Eurasian group that was traveling in New Mexico. This finding aligns with the evidence of Native American presence in the form of ancient footprints and vehicle drag marks at the White Sands during this period. The next major split took place in North America sometime between 17,500 and 14,600 years ago. Some of the people who split from their ancestors made their way to the South and became the Mesoamerican group.

The third split happened in this Mesoamerican group around 13,900 years ago, when it dispersed into four native genetic lineages. These lineages were namely- Chaco Amerindians in the southwest U.S., and Patagonians, Amazonians, and Andeans in South America.

Researchers estimate that the trek measured over 12,000 miles (20,000 kilometers) in length, according to Interesting Engineering. 48 scientists collaborated to recreate migration routes undertaken by humans in this trek. According to the data gathered through genomes, the route ended at Tierra del Fuego in Argentina. High-resolution whole-genome sequencing was conducted to trace genetic markers that were passed down across generations. The examinations not only showcased the period when the population split, but also how these groups adapted to different conditions. 

The study showcased that the population that settled in the Panama-Colombia border around 14,000 years ago exhibited resilience. They faced drastic environmental changes but still thrived through adaptations. 

Experts noted that the Asian population had more genetic diversity compared to the European population, according to Live Science. Ancestors who entered South America possibly dealt with less number of disease-causing organisms compared to those who stayed in Asia. Therefore, they exhibited less genetic diversity than their Asian counterparts, who over the years adapted to the effects of these organisms.

Researchers believe that this indicates that many individuals in the contemporary Indigenous population could have special medical needs. Treatments and drugs in the medical world have historically not considered the indigenous population, experts claimed. Hence, the present processes may not be suitable for the indigenous population because of the lack of genetic diversity. "It is critical to provide tailored healthcare and disease prevention strategies that consider their specific genetic profiles," Kim added.