Meeting Abstract

P3.119  Thursday, Jan. 6  Distribution and structure of genetic variation in Ilyanassa obsoleta (Mollusca: Neogastropoda) PAN, J. W.*; ZIGLER, K. S.; Sewanee: The University of the South; Sewanee: The University of the South panjw0@sewanee.edu

The aim of this study was to examine the structure and distribution of genetic variation in Ilyanassa obsoleta (Say), an important North American marine gastropod. A portion of the mitochondrial COI gene of 51 individuals from 7 locations (5 on the East coast, 2 on the West) was sequenced and added to an existing database of 100 individuals from 4 other locations on the East coast, extending population sampling from Florida to New Brunswick, Canada. A site-by-site comparison showed no significant population structure with the exception of one population in New Brunswick that was isolated from the rest. There was also an overall decrease in nucleotide diversity from south to north. The results suggest that there is limited population structure within I. obsoleta, with significant gene flow linking populations on the East coast save for a few northern populations. Also of note is that populations on the West coast (where I. obsoleta is invasive) have similar levels of genetic diversity to those on the East coast, and have not diverged genetically from East coast populations since they were established. The latitudinal decline in genetic diversity on the East coast is consistent with a gradual northward population extension following the glacial retreat.