What our ancestors’ genomes can tell us about modern health | Explained Premium

Ancient DNA studies provide insights into the genetic makeup, diseases, and lifestyles of our ancestors, with implications for modern healthcare.

Where did we come from? What did our ancestors eat? What adversities did our ancestors face? Why did some of our ancestors suddenly disappear?

These and many such questions have fascinated people for a long time. Ancient DNA (aDNA) studies powered by cutting-edge genomic techniques have opened a window into the past, providing unprecedented insights into the genetic makeup of our ancestors. And by extracting and analysing DNA from ancient skeletal remains, scientists can reconstruct the genetic profiles of these people.

Studies of such ancestral DNA have provided glimpses into the genetic diversity and population dynamics of ancient communities, their migration patterns, interactions, and adaptations to local environments, and even into the diseases these people confronted and how the afflictions shaped human evolution.

For example, genomic technologies have given researchers a way to understand pathogens that spread in the distant past, and trace their origins and evolutionary trajectories. By reconstructing the genomes of these lifeforms, they have been able to piece together the emergence, spread, and adaptation of infectious diseases throughout human history.

In a number of recent papers, researchers have also reported being able to use sequences of aDNA to understand genetic diseases that may have affected ancient humans, and through that open windows onto the medicines and tools that early human communities used. Such insights enrich our knowledge of evolutionary history as well as have implications for modern healthcare, since they can teach us about the diseases to which our genes have rendered us susceptible as well as how health disparities arose between different populations.

For example, some of the more common genetic diseases are the result of chromosomal abnormalities. Many chromosomal abnormalities result in chromosome number changes – that is, extra copies or deletions of entire chromosomes – resulting in different clinical syndromes. For example Down’s syndrome is caused by an extra chromosome 21; Klinefelter’s syndrome due to an extra X chromosome; and Turner syndrome by the loss of one of the two X chromosomes in women.

Chromosomal karyotyping is a method to visualise the complete set of chromosomes in a cell, and is among the best techniques to diagnose such abnormalities. However, karyotyping requires live cells, which in turn requires scientists to adopt laborious methods to culture and stain them.