Chimpanzees, our closest living animal cousins share 98% of our human genes, meaning that for 98% of our genes, there is a similar gene in the chimpanzee genome.Even mammals that look quite different from us share a large percentage of our genes; small and furry mice share 92% our genes.himpanzees, our closest living animal cousins share 98% of our human genes, meaning that for 98% of our genes, there is a similar gene in the chimpanzee genome.