Meeting Abstract

P1.102  Wednesday, Jan. 4  Genetics and color development in a rare melanized and pterin-less morph of a North American lizard (Sceloporus) NYGAARD, K.R.*; HUND, A.K.; RAND, M.S.; Carleton College, Northfield, MN; Carleton College, Northfield, MN; Carleton College, Northfield, MN mrand@carleton.edu

In certain Colorado populations, male prairie lizards (Sceloporus consobrinus) exhibit one of three discrete chin-color morphs (orange, yellow, or white). Orange and yellow coloration is qualitatively pterin based, seasonally labile, quantitatively testosterone dependent, and correlated to male agonistic behavior. Pterin-based chin coloration is absent from the rare white morph. In addition, these males are heavily melanized; the dorsal coloration is significantly darker and much of the blue belly and throat patches are suffused in black. Numerous studies in mammals and birds have shown that variation in degrees of pelt and plumage melanization are attributable to sequence variation in the melanocortin-1 receptor (MC1R) gene. We hypothesized that the variation in degree of melanization we observe in these lizards was due to sequence differences in the MC1R gene. We sequenced MC1R in 40 individual lizards, including four pterin-less melanized morphs and found no sequence variation in this gene. Additionally, unlike the orange and yellow morphs, testosterone administration failed to induce pterin-like color development. We also tested the effects of ultraviolet (UV) light stimulation and dietary carotenoid supplementation on color development and found that neither the addition of UV light, nor dietary carotenoids, with or without testosterone, either enhanced or diminished color development in any morph. Our findings are consistent with the hypothesis that these color morphs are genetically determined and we continue to look for the candidate genes responsible for these pigment differences.