Meeting Abstract
P1.170 Saturday, Jan. 4 15:30 The Effect of Microgeographic Barriers on Gene Flow and Population Differentiation SMITH, C.L.*; HAGUE, M.T.J.; ROUTMAN, E.J.; San Francisco State University; University of Virginia; San Francisco State University camillesfsu@gmail.com
Gene flow is considered to be an important homogenizing force holding a species together. (Jackson and Pounds, 1981; Morjan and Rieseberg, 2004). However, some authors have suggested that gene flow is a weak and therefore evolutionarily irrelevant homogenizing force, and that selection is more likely to be the main reason for species cohesion. (Ehrlich & Raven 1969). To accurately determine the effectiveness of gene flow as a homogenizing force, studies of gene flow must be conducted over a variety of geographic distances. In the present study, we compare the genetic differentiation among populations of two small insectivorous lizards, side-blotched lizard ( Uta stansburiana ) and zebra-tailed lizard (Callisaurus draconoides). The Cima Lava Field in the Mojave National Preserve provides a good opportunity to study gene flow patterns across a variable landscape. The lava field region consists of light granite sands infiltrated by large patches of dark lava, overall about 20 km long. Previous research on U. stansburiana in the same region directly observed the lizard on both lava and granite sands and documented dark and light color polymorphisms (Micheletti et al. 2012). Field observations by our lab suggest that although C. draconoides resides on the sandy washes that surround and sometimes wind through the lava field, it is not able to use the lava rock as habitat. Thus the lava acts as a semi-permeable barrier to Callisaurus but not to Uta. Both species at this site were discovered to have an unusually high levels of both mitochondrial and autosomal genetic diversity (Micheletti et al. 2012, Hague unpublished data).The high amount of diversity provides sufficient genetic variation to enable exploration of the effects of microgeographic barriers on genetic differentiation.
