Universe A: Cerrigydrudion High Street with telegraph poles.
Universe B: Cerrigydrudion High Street whereby electric and telegraph technology somehow escaped us.
Hybridisation is not unusual in nature. It can though cause problems where a wild species interbreeds with a domesticated version. Consider the Wildcat and its declining population due to interbreeding with housecats. Or the problem with Spanish bluebells diluting our wild populations of native Bluebell (hyacinthoides non-scripta)
But has anyone stopped to consider what happens when a Sperm Whale hybridises with a Rowan tree. This one was seen flapping around in hedgerow in Montgomeryshire recently. A worrying development and one for the geneticists I think.