title: Evaluating signatures of glacial refugia for North Atlantic benthic marine taxa.
abstract: A goal of phylogeography is to relate patterns of genetic differentiation to potential historical geographic isolating events. Quaternary glaciations, particularly the one culminating in the Last Glacial Maximum approximately 21 ka (thousands of years ago), greatly affected the distributions and population sizes of temperate marine species as their ranges retreated southward to escape ice sheets. Traditional genetic models of glacial refugia and routes of recolonization include these predictions: low genetic diversity in formerly glaciated areas, with a small number of alleles/haplotypes dominating disproportionately large areas, and high diversity including "private" alleles in glacial refugia. In the Northern Hemisphere, low diversity in the north and high diversity in the south are expected. This simple model does not account for the possibility of populations surviving in relatively small northern periglacial refugia. If these periglacial populations experienced extreme bottlenecks, they could have the low genetic diversity expected in recolonized areas with no refugia, but should have more endemic diversity (private alleles) than recently recolonized areas. This review examines evidence of putative glacial refugia for eight benthic marine taxa in the temperate North Atlantic. All data sets were reanalyzed to allow direct comparisons between geographic patterns of genetic diversity and distribution of particular clades and haplotypes including private alleles. We contend that for marine organisms the genetic signatures of northern periglacial and southern refugia can be distinguished from one another. There is evidence for several periglacial refugia in northern latitudes, giving credence to recent climatic reconstructions with less extensive glaciation.
authors.affiliation: School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom. c.maggs@qub.ac.uk
authors.forename: Christine A
authors.initials: CA
authors.lastname: Maggs
authors.forename: Rita
authors.initials: R
authors.lastname: Castilho
authors.forename: David
authors.initials: D
authors.lastname: Foltz
authors.forename: Christy
authors.initials: C
authors.lastname: Henzler
authors.forename: Marc Taimour
authors.initials: MT
authors.lastname: Jolly
authors.forename: John
authors.initials: J
authors.lastname: Kelly
authors.forename: Jeanine
authors.initials: J
authors.lastname: Olsen
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Perez
authors.forename: Wytze
authors.initials: W
authors.lastname: Stam
authors.forename: Risto
authors.initials: R
authors.lastname: Väinölä
authors.forename: Frédérique
authors.initials: F
authors.lastname: Viard
authors.forename: John
authors.initials: J
authors.lastname: Wares
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D044822:Biodiversity; D002980:Climate; D004272:DNA, Mitochondrial / Q000235:genetics*; D005787:Gene Frequency; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D046448:Ice Cover; D008957:Models, Genetic; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial