Fig. 2

Foregut fermentation has independently evolved twice in mammals, first in Rumantia, a lineage of cetartiodactlys that includes cow, sheep, moose, and giraffe—and then again in colobus, langur, and proboscis monkeys. The appearance of this mode of digestion has been accompanied by the independent recruitment of lysozymes as a bacteriolytic enzyme in the stomach and gene duplication of pancreatic RNase which is secreted by the pancreas RNase1 gene in homologous, but the subsequent gene duplication and functional specialization occurred independently, but in parallel