Genomic differences in two bird subspecies shed new light on mechanics of testosterone-mediated evolution
Date: June 15, 2016
Source: Indiana University
A pair of studies led by Indiana University researchers provide new evidence that when it comes to evolution, the testes may play a key role.
The research, led by Kimberly Rosvall, assistant professor in the IU College of Arts and Sciences' Department of Biology, finds that the testes -- or gonads -- have a greater impact than previously thought in evolution. The research was conducted in two subspecies of dark-eyed junco, a type of American sparrow.
The white-winged junco, or Junco hyemalis aikeni, is found in the Black Hills of South Dakota. The slate-colored junco, or Junco hyemalis carolinensis, is from the Appalachian Mountains in Virginia. The first is larger and more aggressive; the other is smaller and more docile.
The studies are published in the journals of Hormones and Behavior and of Integrative and Comparative Biology.
The first paper compares the subspecies in their expression of enzymes that make testosterone within the gonad. The second paper investigates how the subspecies' gonads differ in the expression of stress hormone receptor genes, which are known to lower testosterone.