NO IMMUTABLE SPECIES. “As far as DNA is concerned, however, the supposed walls between species are not nearly so impermeable. Up in the branches of the great tree of life, we are no longer immersed in the ancient communal pool that watered its tangled roots. Yet we cannot escape the winds of promiscuity. Even today – as was true from the start – ‘our’ genes are not ours alone.”
https://aeon.co/essays/genes-that-jump-species-does-this-shake-the-tree-of-life