Cows have conservative hormones.

Cows have conservative chromosomes

A cow's chromosomes are virtually uncharted territory, compared with the genetic maps of human and mouse chromosomes. Whereas the human map currently contains more than 800 genes and the mouse map about 750, only 35 genes have been placed on the bovine map and geneticists do not yet know which of the cow chromosomes correspond to the different areas of the map. A recent study, however, indicates that the cow genetic map closely resembles the human map.

The genes for 32 proteins similar in cattle, humans and mice have been mapped in all three species. The maps of the cattle and the humans differ for only three of these genes, but the maps of the mice and humans differ in nine locations, report James E. Womack and Yvonne D. Moll, of Texas A&M University in College Station, in the most recent (January/February) JOURNAL OF HEREDITY. This finding suggests that cows, like primates and cats, have evolutionarily stable chromosomes, as opposed to mice, Chinese hamsters and dogs, whose chromosomes have undergone more extensive rearrangement during evolution.