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Mitonuclear conflict — a struggle between the genes in a cell’s nucleus and its mitochondria — might sometimes split species in two.
How many Neanderthals were there? Archaeology and genetics have given very different answers. A new study reconciles them and reveals the lost history of these ancient people — including an early brush with extinction.
The discovery that viruses move between species unexpectedly often is rewriting ideas about their evolutionary history — and may have troubling implications for the threat from emerging diseases.
Hybrids, once treated as biological misfits, play a vital role in the evolution of many animal species. Now conservationists are trying to reconcile that truth with policies.