Meeting Abstract

118.5  Tuesday, Jan. 7 11:15  Adaptive genetic differentiation across the depth ranges of intertidal invertebrates PENNOYER, K*; FURINESS, S; COCKETT, P; GURSKI, L; BIRD, C; Texas A and M University -Corpus Christi Kelly.Pennoyer@tamucc.edu

The drivers affecting realized species ranges are important in the prediction of global climate change impacts on biotic communities. Intertidal species are particularly well suited to studies of vertical range limits due to the extremely narrow gradient in habitat characteristics from the marine to terrestrial realm. Realized vertical species ranges are the result of both biotic and abiotic factors, where lower limits are most often directly controlled by competition and predation and upper limits are more directly impacted by abiotic factors and positive biotic interactions. Here we employ genome-wide analyses of genetic variation (~20,000 SNPs) in an oviparous snail (Littoraria pintado) and a broadcast-spawning limpet (Cellana exarata) at the upper, mid, and lower ends of their vertical ranges across several Hawaiian Islands to test for parallel patterns of selection. L. pintado was characterized by much less population structure among islands than C. exarata. In both L. pintado and C. exarata, several genes experienced significant levels of purifying selection at the upper and lower ends of their ranges. We also identified a handful of genes experiencing disruptive selection between the upper and lower shore limits. We are presently working on identifying the adaptive genes, such as HSP70, and determining whether they are likely to be responding to biotic or abiotic stressors. Overall, we find that RADseq and population genomic techniques are quite effective at identifying critical genetic variation that affects survival, and species range limits.