title: Mitochondrial genome diversity and population structure of the giant squid Architeuthis: genetics sheds new light on one of the most enigmatic marine species.
abstract: Despite its charismatic appeal to both scientists and the general public, remarkably little is known about the giant squid Architeuthis, one of the largest of the invertebrates. Although specimens of Architeuthis are becoming more readily available owing to the advancement of deep-sea fishing techniques, considerable controversy exists with regard to topics as varied as their taxonomy, biology and even behaviour. In this study, we have characterized the mitochondrial genome (mitogenome) diversity of 43 Architeuthis samples collected from across the range of the species, in order to use genetic information to provide new and otherwise difficult to obtain insights into the life of this animal. The results show no detectable phylogenetic structure at the mitochondrial level and, furthermore, that the level of nucleotide diversity is exceptionally low. These observations are consistent with the hypotheses that there is only one global species of giant squid, Architeuthis dux (Steenstrup, 1857), and that it is highly vagile, possibly dispersing through both a drifting paralarval stage and migration of larger individuals. Demographic history analyses of the genetic data suggest that there has been a recent population expansion or selective sweep, which may explain the low level of genetic diversity.
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.
authors.forename: Inger
authors.initials: I
authors.lastname: Winkelmann
authors.forename: Paula F
authors.initials: PF
authors.lastname: Campos
authors.forename: Jan
authors.initials: J
authors.lastname: Strugnell
authors.forename: Yves
authors.initials: Y
authors.lastname: Cherel
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Smith
authors.forename: Tsunemi
authors.initials: T
authors.lastname: Kubodera
authors.forename: Louise
authors.initials: L
authors.lastname: Allcock
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Kampmann
authors.forename: Hannes
authors.initials: H
authors.lastname: Schroeder
authors.forename: Angel
authors.initials: A
authors.lastname: Guerra
authors.forename: Mark
authors.initials: M
authors.lastname: Norman
authors.forename: Julian
authors.initials: J
authors.lastname: Finn
authors.forename: Debra
authors.initials: D
authors.lastname: Ingrao
authors.forename: Malcolm
authors.initials: M
authors.lastname: Clarke
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D049832:Decapodiformes / Q000145:classification / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D054629:Genome, Mitochondrial; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D004272:DNA, Mitochondrial