Palaeogenomics and human evolution

Genomics has opened up our understanding of ancient hominins and human evolution.

Genomics is an area within genetics that concerns the sequencing and analysis of an organism’s genome. The genome is the entire DNA content that is present within one cell of an organism.

Genomics work has been prevalent within flora and fauna studies and research into human disease. It’s also proving a useful tool for looking at ancient DNA.

This work, called palaeogenomics, feeds our human curiosity to know more about ourselves and our origins, but it also has implications for our health and wellbeing in the modern day.

Palaeogenomics

Svante Pääbo, Director of the Max Planck Institute for Evolutionary Anthropology, is often referred to as a ‘father’ of palaeogenomics – the genetic study of early humans and other ancient populations. Svante realised that, if intact DNA could be recovered from Neanderthals and other early human fossils, comparing the DNA with the DNA of modern humans and great apes would revolutionise research into human evolution.

Sequencing the Neanderthal genome

Svante and his colleagues began the task of sequencing the Neanderthal genome in 2005. The publication of this work in its early phase in 2010 provided evidence that modern humans and Neanderthals had interbred outside of Africa.

Other key findings within this research were that all non-Africans today share between 1.5% and 2.1% of DNA that has been inherited from Neanderthals.

Scientists have also been able to pinpoint certain genes we’ve inherited from our Neanderthal forebears – genes that are associated with keratin, type 2 diabetes, nicotine addiction and Crohn’s disease.

DNA studies have also shown when interbreeding occurred between Neanderthals and other hominin species – the more Neanderthal DNA that is present, the more recently the interbreeding occurred.

How can ancient DNA help us today?

This work has implications for health and medicine. We know for example that some of our genetic legacy is responsible for genes that code for things like lupus, diabetes and addictions, and because these come from Neanderthal DNA, we know that there must be variations in the proportion of these genes in different populations. If we can understand the different inputs and proportions of DNA from these sources in different groups, we can contribute more to understanding problems in health amongst different human groups.

The same goes for DNA linked with diseases. As we build more genetic libraries from the past, we can understand more about major pathogens that have infected humans. We can see when diseases spread in the past and how. Recent work, for example, on the bubonic plague shows that Bronze Age people had this. It also shows that the Yersinia pestis bacterium that causes it was more or less the same as we see it today, meaning that it didn’t mutate and was the same killer seen in the Black Death plague of 1347.

Studies of dental plaque from past humans is shedding light on the bacterial microbiome present, which is a treasure trove of past information on the bacteria humans carry.

‘Out of Africa’ and DNA

Prior to palaeogenomics, genetics had already played an important role in progressing our understanding of human evolution and migration. New Zealand molecular biologist Allan Wilson and two of his students, Rebecca Cann and Mark Stoneking, used emerging molecular technology to illuminate the origins of modern humans, describing a ‘mitochondrial Eve’ – a small group of female ancestors living in Africa and from whom all people alive today are descended.

Learn more about other technologies that are contributing to our knowledge of human evolution in: Evolutionary research – advancing our understanding of us.