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
Palaeogenomics is revolutionising our understanding of human evolution and who we are. Oxford University Professor of Archaeological Science Tom Higham explains what palaeogenomics is and some of the exciting findings coming from this field.
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.
Our surviving Neanderthal genes
Everyone living outside of Africa today has a small amount of Neanderthal DNA. Oxford University Professor of Archaeological Science Tom Higham explains some of the traits we’ve inherited from our ancient evolutionary relatives.
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.
Palaeogenomics and interbreeding
DNA is providing intriguing insights into human evolution. Oxford University Professor of Archaeological Science Tom Higham talks about interbreeding, our Neanderthal genes and the likelihood of multiple introgressions.
Jargon alert
In genetics, introgression, also known as introgressive hybridisation, is the movement of a gene (gene flow) from one species into the gene pool of another.
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.
The evidence for ‘out of Africa’
The ‘out of Africa’ model is the theory that the Homo genus migrated out from Africa to populate the rest of the world. Oxford University Professor of Archaeological Science Tom Higham explains the model and the research that has supported it.
Learn more about other technologies that are contributing to our knowledge of human evolution in: Evolutionary research – advancing our understanding of us.
Related content – Genomics
Take a look at some of the diverse fields employing genomic research.
In 2010, the genome for the golden delicious apple was published. This work had some unexpected findings and will impact on fruit breeding.
The nutrigenomics project sought to understand the links between individuals, disease and food.
Read about the work of Otago University researchers who have sequenced the mitochondrial DNA from several human samples extracted from the Wairau Bar burial site: DNA diversity in early New Zealanders.
What the apple genome can tell us
The genome sequence of the Golden Delicious apple was published in 2010. Scientists at Plant & Food Research, including Andy Allan, contributed to the project. Here, Andy describes how the apple genome will increase the speed of apple breeding programmes, and what the genome can tell us about the apple’s history.
Useful links
Palaeogeneticist Svante Pääbo was awarded the 2022 Nobel prize in physiology or medicine for his work on the genomes of extinct hominins. Learn more about his research at the Max Planck Institute for Evolutionary Anthropology.
Listen to Professor Rebecca Cann on RNZ, talking about her work with Allan Wilson that showed modern humans evolved from a single African population.
Read more about the discovery of Bronze Age victims of the bubonic plague and how disease might have driven mass migrations.
Check out our Human evolution Pinterest board for more resources.
Curious to test your own DNA? Read Five things to consider before ordering an online DNA test from The Conversation.
Acknowledgement
The Science Learning Hub would like to acknowledge the Allan Wilson Centre for Molecular Ecology and Evolution, which sponsored and recorded Professor Tom Higham’s lecture When Neanderthals and Modern Humans (and Denisovans) Met: Human Evolution from 60,000–30,000 Years Ago in September 2015.
