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So they're mainly isolated now - but elephants and their ancestors also mixed a lot. So conservation was not being done everywhere in Africa but only to conserve some groups.īut we now know that the forest elephants in Western Africa, which are half the size of the savannah elephants, are very distinct and special, and need to be conserved just as much as the savannah elephants. Conservation laws usually try to focus on preserving at least some populations of the species, and African elephants were often, by some people, argued to be the same species because of these hybrid zones. That's one of the big implications of the study. But if you look at the forest elephants from western Africa and the savannah elephants from South Africa and East Africa, there's been essentially no gene exchange amongst their ancestors for the last half million years. They hybridize at their boundaries and there are known hybrid groups. So for example, in Africa today there are two species of elephants that are genetically extremely distinct from each other. I think that combined with this mixture are long periods of extreme isolation. In some elephants it stopped, and in some elephants it continues. So a huge mixture at multiple time depths is characteristic of the elephants.

But with this high-resolution, whole-genome data, we can figure out that great mixture events have occurred in the past.įor example, the European straight-tusked elephant is a mixture of a minimum of three very divergent lineages: one related to mammoths and Asian elephants another related to forest elephants from western Africa and another related to the common ancestor of forest and savannah elephants both from Africa. The biggest take-home message is really that mixture of very different elephant populations occurred repeatedly over elephant history.īefore this work, I was involved in studies that took the very thin data we had and worked out the average relationships amongst elephants, figured out which groups were closest to which other groups. So it was really an amazing set of data, and we were able to analyze it to obtain a qualitatively different picture of elephant population history than we had before. Also, ancient DNA from the first Columbian elephants, which are an American temperate mammoth and also a very high-quality genome of an ancient European straight-tusked elephant that was more than 100,000 years old. This study ended up being a big ancient DNA study as well, where we report the first ancient DNA from the extinct Mastodon, which is a distant cousin of the elephant. We decided eventually to publish it by not just presenting the genome of the elephant, but also presenting the genomes of all diverse living elephants, and also diverse extinct elephants from which we obtained ancient DNA. We sequenced a high-quality genome of the iconic elephants - the savanna and African elephant - and it took us a long time to publish it. This study started as the Elephant Genome Project more than a decade ago. But also that current elephants in Africa have been isolated for so long that they should be considered two separate species, which could affect conservation efforts. He says the findings show that elephant species have often mixed and mingled over the millennia. David Reich of the Broad Institute and Harvard helped lead the consortium that has just published its findings - the most sweeping analysis yet of elephants and their extinct relatives - in the Proceedings of the National Academy of Sciences. Using powerful new techniques for analyzing DNA, researchers have sequenced not just the genes of modern elephants but of their extinct ancestors and relatives as well: mastodons, woolly mammoths and straight-tusked elephants.ĭr. (Megan Coughlin/Flickr) This article is more than 4 years old. Elephants in Tarangire National Park in Tanzania.