title: Low worldwide genetic diversity in the basking shark (Cetorhinus maximus).
abstract: The basking shark (Cetorhinus maximus) is found in temperate waters throughout the world's oceans, and has been subjected to extensive exploitation in some regions. However, little is known about its current abundance and genetic status. Here, we investigate the diversity of the mitochondrial DNA control region among samples from the western North Atlantic, eastern North Atlantic, Mediterranean Sea, Indian Ocean and western Pacific. We find just six haplotypes defined by five variable sites, a comparatively low genetic diversity of pi=0.0013 and no significant differentiation between ocean basins. We provide evidence for a bottleneck event within the Holocene, estimate an effective population size (Ne) that is low for a globally distributed species, and discuss the implications.
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH13LE, UK. a.r.hoelzel@durham.ac.uk
authors.forename: A Rus
authors.initials: AR
authors.lastname: Hoelzel
authors.forename: Mahmood S
authors.initials: MS
authors.lastname: Shivji
authors.forename: Jennifer
authors.initials: J
authors.lastname: Magnussen
authors.forename: Malcolm P
authors.initials: MP
authors.lastname: Francis
mesh_terms: D000818:Animals; D020137:Base Pair Mismatch / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D014644:Genetic Variation; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D009792:Oceans and Seas; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012343:RNA, Transfer / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D012754:Sharks / Q000235:genetics*
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial; D012343:RNA, Transfer