In a newfangled written report , scientists have been able-bodied to use peptides demand from an ancient hominin to settle its sexual activity – and at 3.5 million geezerhood old , they trust it to be the oldest such specimen to have been successfully analyze in this direction .

As palaeoanthropologists have describe more and more ossified specimen ofancient hominins , they have also find vast variation between individual – even within the same specie . In that sensation , our distant relatives are n’t all that different from us .

However , when it comes to such primitive specimens , it ’s one affair to make observations of variant and entirely another to nail what ’s behind it . While scientists can extract and investigate the potentially causative clump of desoxyribonucleic acid of living mintage with relative ease , the same ca n’t be said for fogey ; biological molecules degrade over prison term , and that makes things guileful .

That ’s where the comparatively new field of palaeoproteomics – the field of proteins from ossified material – comes in . Proteins can also tell scientists a lot about an mortal and incline to survive better through the age compared to DNA . Theoretically , then , palaeoproteomics could clew us into the reasonableness behind variation , include sexual dimorphism .

After some feasibleness studies , a team of researchers has now done precisely that . They used a minimally invasive technique to elicit and analyse peptide – short strings of amino Elvis , which are the building blocks of protein – from the tooth enamel of anAustralopithecus africanusspecimen found in South Africa ’s Sterkfontein cave .

Among the 118 peptides the squad recovered , there were some alone to amelogenin , a protein involved in the development of tooth enamel . The factor that encodes it has two dissimilar adaptation : AMELXandAMELY , severally find on the X and Y gender chromosomes . They lead to the production of slightly different kind of the protein , which means they can be used to specify whether an individual has a Y chromosome , and thus deduce their sexual activity .

In this compositor’s case of theA. africanusspecimen , the investigator identified four peptides unparalleled to AMELX and 3 to AMELY . Therefore , they concluded with a eminent stage of confidence that the individual being canvas was a male person .

While palaeoproteomics haspreviouslybeen used before to square off the sex of aHomo antecessorspecimen , theA. africanusspecimen – which is dated at 2 to 3.5 million years one-time – is suppose to be the oldest hominin that it ’s been successfully used on .

The researchers hope that their findings illustrate the potential might of palaeoproteomics method in the wider domain of human paleontology .

“ Even though palaeoproteomics is still in its early childhood and circumspection should be used in translate the results , it is still poised to be able to serve some of human paleontology ’s most fundamental interrogative about sexual dimorphism , fluctuation and phylogenesis , ” they write . “ [ P]alaeoproteomics inquiry is at the leaflet of singular discoveries . ”

The study is published in theSouth African Journal of Science .