Perna perna metadata and genotypic data

Studies investigating gene flow in sessile or sedentary marine species
typically draw conclusions about larval dispersal by investigating genetic
structure of adults. Here, we generated microsatellite data from adults,
recruits, settlers and planktonic larvae of the brown mussel, Perna perna,
from the south-east coast of South Africa, and identified a consistent
mismatch in genetic structure between the adults and all earlier life
stages. While adults could be assigned to two major geographical groups
(western and eastern), most of the early-stage mussels were strongly
affiliated with the eastern group. This result suggests that few of the
early-stage individuals present in the western portion of the sampling
range will become part of the adult population. Our findings highlight the
importance of post-settlement processes as key drivers of population
structure and caution against the exclusive use of genetic data generated
from adults to assess population connectivity facilitated by the dispersal
of planktonic propagules.