Modern elephants of different species no longer mate with each other, unlike ancient elephant, mastodon and mammoth species, which thus exchanged genes that allowed them to adapt to new environments and climates, researchers announced on Monday.
The study, published in the journal Proceedings of the National Academy of Sciences, sequenced 14 genomes, including two mammodontes, a mammoth, an ancient elephant species, and modern African and Asian elephants.
“Hybridization could help explain why mammoths were as successful in living in such different environments and for such a long time,” says Hendrik Poinar, one of the authors of the study and a geneticist at McMaster University in Canada.
“These genomic data show us that biology is complicated and that evolution does not happen in an organized, linear way,” he continues.
One of the extinct elephant species that has long fascinated the experts was the elephant with straight tusks (Palaeoloxodon antiquus). It was traditionally assimilated to today’s Asian elephants because of the similarities between the shape of their skulls and the size of their teeth.
But scientists have actually discovered that the former was “a crossed breed with parts of its genetic makeup from an old African elephant, the woolly mammoth and the forest elephants”.
This study “reveals major multiple hybridization events between the different ancient species, highlighting how this played a fundamental role in the evolution of the elephant,” say the scientists.
In Africa, savanna elephant and forest elephant are two different species. But the study shows no genetic evidence of hybridization between these two species, “suggesting that they have lived in near-complete isolation for the last 500,000 years, despite the fact that they live in neighboring environments”.
Elephants, once numerous on land, are becoming increasingly rare, poaching being responsible for the deaths of thousands of them each year.