Meeting Abstract

P3.2  Jan. 6  Population genetic structure of a sympatric squid-Vibrio symbiosis in the Mediterranean Sea using nested clade analysis ZAMBORSKY, D.J.*; PASKADI, T.R.; NISHIGUCHI, M.K.; New Mexico State University; New Mexico State University; New Mexico State University zambo@nmsu.edu

Squids from the genus Sepiola (Cephalopoda: Sepiolidae) living sympatrically in the Mediterranean Sea form a mutualistic symbiosis with two species of the Vibrio genus: V. fischeri and V. logei. Environmentally transmitted symbionts inhabit the light organs and produce ventrally-directed luminescence used in anti-predatory behavior. The light organ expulses symbiotic bacteria daily, and is subsequently re-colonized by the remaining Vibrio bacteria in the light organ. This diurnal event has led to phylogeographical variation within the squid-Vibrio system in other regions of the world (Indo-Pacific). Although the symbiosis amongst sympatric Sepiola species and both species of Vibrio in the Mediterranean has been well documented; the genetic structure of the host squid and Vibrio symbiont has not been described. Using nested-clade analysis we have investigated the genetic variation within host and bacterial symbiont populations in the geographical range of the Mediterranean. The results demonstrate a localization of haplotypes in the host squid populations closely related to the physical range of the host. Vibrio symbionts show a broader number of haplotypes over a wider geographic area suggesting a strong influence of migratory forces, both biotic and abiotic. Biotic factors such as host movement within the Mediterranean as well as abiotic influences such as currents may contribute to the diversiform genetic architecture of the symbiont population observed in this study.