Humans contain ‘alien’ genes not passed on from our ancestors, researchers have discovered.
The say we acquired essential ‘foreign’ genes from microorganisms co-habiting their environment in ancient times.
The study challenges conventional views that animal evolution relies solely on genes passed down through ancestral lines – and says the process could still be going on.
The research published in the open access journal Genome Biology focuses on the use of horizontal gene transfer, the transfer of genes between organisms living in the same environment.
‘This is the first study to show how widely horizontal gene transfer (HGT) occurs in animals, including humans, giving rise to tens or hundreds of active ‘foreign’ genes,’ said lead author Alastair Crisp from the University of Cambridge.
‘Surprisingly, far from being a rare occurrence, it appears that HGT has contributed to the evolution of many, perhaps all, animals and that the process is ongoing, meaning that we may need to re-evaluate how we think about evolution.’
It is well known in single-celled organisms and thought to be an important process that explains how quickly bacteria evolve, for example, resistance to antibiotics.
HGT is thought to play an important role in the evolution of some animals, including nematode worms which have acquired genes from microorganisms and plants, and some beetles that gained bacterial genes to produce enzymes for digesting coffee berries.