J.B.S. Haldane was a famous Scottish turned naturalized Indian biologist and mathematician who loved going barefoot and studying genetics, particularly evolution in animals. What does this Mr. Haldane have to do with the colorful Western Scrub-Jay? Researchers discovered that there are three distinct sub-species of Western Scrub-Jay. They used the Haldane rule which states that, if species hybrids of one sex only are inviable or sterile, the afflicted sex is much more likely to be heterogametic (XY) than homogametic (XX). In plain terms this refers to dominance in genes. A team led by Occidental's John E. McCormack discovered the following populations have unique genetics: A. californica (Pacific Slope); A. woodhouseii (Interior US plus Edwards Plateau plus Northern Mexico); A. sumichrasti (Southern Mexico).

What, if any, impact this discovery has on conservation remains to be seen.

Source: Gowen, Fiona C; Maley, James M; Cicero, Carla; Peterson, A Townsend; Faircloth, Brant C; Warr, T Caleb; and McCormack, John E. Speciation in Western Scrub-Jays, Haldane’s rule, and genetic clines in secondary contact, BMC Evolutionary Biology 2014, 14:135.

Photo by Maggie Smith.