1 research outputs found
Stable populations in unstable habitats: temporal genetic structure of the introduced ascidian Styela plicata in North Carolina
14 páginas, 3 tablas, 4 figuras.The analysis of temporal genetic variability is
an essential yet largely neglected tool to unveil and predict
the dynamics of introduced species. We here describe
the temporal genetic structure and diversity over time of
an introduced population of the ascidian Styela plicata
(Lesueur, 1823) in Wilmington (North Carolina, USA,
34°08′24″N, 77°51′44″W). This population suffers important
salinity and temperature changes, and in June every
year we observed massive die-offs, leaving free substratum
that was recolonized within a month. We sampled 12–14
individuals of S. plicata every 2 months from 2007 to 2009 (N = 196) and analyzed a mitochondrial marker (the gene
cytochrome oxidase subunit I, COI) and seven nuclear
microsatellites. Population genetic analyses showed similar
results for both types of markers and revealed that most
of the genetic variation was found within time periods.
However, analyses conducted with microsatellite loci also
showed weak but significant differences among time periods.
Specifically, in the samplings after die-off episodes
(August–November 2007 and 2008) the genetic diversity
increased, the inbreeding coefficient showed prominent
drops, and there was a net gain of alleles in the microsatellite
loci. Taken together, our results suggest that recruits
arriving from neighboring populations quickly occupied
the newly available space, bringing new alleles with them.
However, other shifts in genetic diversity and allele loss
and gain episodes were observed in December–January and
February–March 2008, respectively, and were apparently
independent of die-off events. Overall, our results indicate
that the investigated population is stable over time and
relies on a periodic arrival of larvae from other populations,
maintaining high genetic diversity and a complex interplay
of allele gains and losses.This research was supported
by a grant from the United States–Israel Binational Science Foundation
(BSF), Jerusalem, Israel (number 2014025), the Spanish Government
project CTM2013—48163—and the Catalan Government Grant
2014SGR-336 for Consolidated Research Groups.Peer reviewe