Mitochondrial DNA, inherited down the female line, shows unusually low diversity in taurine cattle compared with their wild ancestor. Modelling from ancient Near Eastern samples has estimated the founding female population at approximately eighty animals, though the confidence interval around that figure is wide.
The aurochs itself, Bos primigenius, was a substantially larger animal than any modern breed, with bulls standing well over 1.7 metres at the shoulder. It persisted in the forests of Poland until the last recorded individual died in the Jaktorów forest in 1627, making it one of the few wild ancestors of a livestock species whose extinction was documented in writing.
Indicine cattle, the humped zebu of South Asia, come from a separate aurochs domestication and contribute a distinct maternal lineage. The two groups interbreed freely, and much of the world's cattle population is now admixed, which means the narrow taurine bottleneck describes one strand of an increasingly blended ancestry rather than the whole of it.