The origins of contemporary humans have been debated for several years. High-resolution genetic data made available with recent advances in technology have made it possible to compare genomes between different human populations. The recent advancements in ancient genome sequencing, where DNA is extracted from ancient skeletons dating back to hundreds and even thousands of years ago, have also made it possible to compare current human genomes with those of our ancestors.

The front cover of the October 2016 edition of Nature magazine featured an artistic interpretation of the study, designed by Estonian artist Markus Kasemaa.

Genetic studies have so far traced today’s non-African populations to a major human migration event – an exodus of modern humans out of Africa that happened in a single wave around 75,000 years ago, whereby after evolving in Africa, humans started to colonise different parts of the world.

However, a recent study suggested that another human dispersal out of Africa happened around 120,000 years ago. In the study, whole human genomes from 148 different worldwide human populations and ancient genomes were compared and analysed, eventually leading to the identification of the genetic trace from the extinct human population that is still present in the current indigenous Papuans but not present in the worldwide human population.

These results, a remarkable 45,000 years before the main ‘out of Africa’ human expansion, shed further light on our evolutionary past and help us understand better some of the challenges that our ancestors faced when pioneering into new environments.

The study… eventually led to the identification of the genetic trace from the extinct human population that is still present in the current indigenous Papuans but not present in the worldwide human population

The study was published in the scientific journal Nature, under the title ‘Genomic analyses inform on migration events during the peopling of Eurasia’. It was also listed among the top 10 final scientific breakthroughs of 2016 by the journal Science.

The study was led by researchers from the University of Cambridge and University of Tartu and it was made possible from the extensive collaboration effort of researchers from 74 different research groups from all over the world.

Dr Alexia Cardona, a Maltese researcher, was one of the authors of the study for which she conducted genome-wide analyses. She is currently a research fellow at the University of Cambridge where she is investigating the genetics and epigenetics of the aetiology of Type 2 diabetes, obesity and ageing.

Science magazine’s top 10 science breakthroughs of 2016 may be viewed at the following link: www.sciencemag.org/news/2016/12/ai-protein-folding-our-breakthrough-runners.

The original article in Nature journal may be viewed at the following link: www.nature.com/nature/journal/v538/n7624/full/nature19792.html.