For the first time, scientists have successfully determined the sex of an ancient human relative using palaeoproteomics, a cutting-edge technique that analyses proteins preserved in fossilised tooth enamel. The subject of this study? A male Australopithecus africanus, a hominin species that lived in South Africa between 3.5 and 2 million years ago.
This breakthrough pushes the limits of what we can learn from ancient remains, potentially unlocking new insights into human evolution. The study, published in the South African Journal of Science on 7 February 2025, is part of a special issue marking the 100th anniversary of the discovery of the Taung Child—the first Australopithecus fossil ever found.
In 1925, Australian anthropologist Raymond Dart first identified Australopithecus africanus as a human relative, a bold and controversial claim at the time. Now, a century later, molecular science is transforming how we study our ancient past.
A technological leap in human origins research
The fossil under study was discovered in the Sterkfontein Caves, a site renowned for its wealth of ancient hominin remains. Determining the sex of prehistoric individuals has traditionally relied on skeletal characteristics, but the incomplete nature of most fossils often makes this difficult.
This is where palaeoproteomics comes into play. Using a minimally invasive method, scientists extracted over 100 peptides—short chains of amino acids that make up proteins—from the tooth enamel of an Australopithecus africanus individual.
One protein, amelogenin, plays a key role in tooth development and is produced differently in males and females. By analysing its molecular structure, researchers determined that this ancient hominin was male—a scientific first for fossils of this age.
This development is a game-changer for palaeoanthropology, allowing scientists to determine the sex of individuals in species where complete skeletons are rare.
This technique has the potential to resolve long-standing debates about sexual dimorphism in early hominins and how males and females may have differed in size, behaviour, and roles within their groups.
Why this discovery is significant
Identifying the sex of ancient hominins is far more than an academic achievement. It provides crucial information about social structures, biological differences, and evolutionary trends in our early ancestors.
Australopithecus africanus lived during a period of dramatic evolutionary change, making this data invaluable for understanding how early hominins developed.
The Sterkfontein Caves, where this fossil was found, are part of the Cradle of Humankind, a UNESCO World Heritage Site that has yielded fossils from at least six hominin species, including Homo naledi (who lived between 335,000 and 236,000 years ago).
With palaeoproteomics, researchers can now accurately identify the sex of individuals from these species, improving our understanding of their biology and behaviours. Since proteins survive much longer than DNA, this technique could also be applied to even older fossils where genetic material has completely degraded.
In fact, palaeoproteomics was originally developed 30 years ago and has already been used to analyse an 80-million-year-old dinosaur, Brachylophosaurus.
The future of palaeoproteomics
This study is just the beginning. The researchers plan to extend their work to other fossils from different regions and time periods, with the hope of rewriting parts of the human evolutionary tree.
By comparing preserved proteins across multiple hominin species, scientists could uncover hidden relationships and refine our understanding of how our ancestors evolved.
Expanding the use of palaeoproteomics to different environments could reveal how climate and geography influenced human evolution. Some hominin fossils have been found in extreme conditions, from humid rainforests to dry deserts, making DNA preservation challenging.
If this technique proves reliable in other settings, it could revolutionise our ability to extract biological data from some of the most elusive fossils.
Ultimately, these findings mark a new era in human origins research, providing scientists with tools to study ancient hominins with unprecedented precision. With each breakthrough, we get closer to unravelling the complex history of our species—one protein at a time.
This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.
