Shallow gene pools in the high intertidal: extreme loss of genetic diversity in viviparous sea stars (Parvulastra).
We document an extreme example of reproductive trait evolution that affects population genetic structure in sister species of Parvulastra cushion stars from Australia. Self-fertilization by hermaphroditic adults and brood protection of benthic larvae causes strong inbreeding and range-wide genetic poverty. Most samples were fixed for a single allele at nearly all nuclear loci; heterozygotes were extremely rare (0.18%); mitochondrial DNA sequences were more variable, but few populations shared haplotypes in common. Isolation-with-migration models suggest that these patterns are caused by population bottlenecks (relative to ancestral population size) and low gene flow. Loss of genetic diversity and low potential for dispersal between high-intertidal habitats may have dire consequences for extinction risk and potential for future adaptive evolution in response to climate and other selective agents.
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
Carson C
CC
Keever
Jonathan B
JB
Puritz
Jason A
JA
Addison
Maria
M
Byrne
Richard K
RK
Grosberg
Robert J
RJ
Toonen
Michael W
MW
Hart
D000818:Animals; D005788:Gene Pool; D014644:Genetic Variation; D013215:Starfish / Q000235:genetics* / Q000502:physiology; D055871:Tidal Waves; D052286:Viviparity, Nonmammalian
Asterinidae; dispersal; inbreeding; self-fertilization