Journal
<p>Due to the sparse and unstable nature of insular<br />
freshwater habitats, marine larval dispersal of amphidromous<br />
species is considered a critical element of population<br />
persistence. We assessed population genetic structure<br />
of freshwater prawn Macrobrachium lar across its range<br />
that encompasses two biogeographic barriers: the vast open<br />
ocean separating Western and Central Pacific regions and<br />
the Indo-Malay archipelago separating Indian and Pacific<br />
oceans. A total of 173 samples collected from 21 islands<br />
throughout the Indo-Pacific were sequenced at 16S and 28S<br />
rDNA. We observed distinct genetic isolation of populations<br />
located at the eastern and southwestern edge of the<br />
species range but no evidence of an effect of the Indo-<br />
Pacific barrier. Differentiation patterns are consistent with<br />
a stepping-stone model of dispersal. Genetic differences of<br />
Central Pacific populations may reflect founder events<br />
associated with colonization of isolated islands, or be a<br />
signature of a past bottleneck after population depletion<br />
caused by drastic climatic events.</p>
