title: Genetic diversification and demographic history of the cactophilic pseudoscorpion Dinocheirus arizonensis from the Sonoran Desert.
abstract: Sequence data from a segment of the mitochondrial cytochrome c oxidase subunit I (COI) gene were used to examine phylogenetic relationships, estimate gene flow and infer demographic history of the cactophilic chernetid pseudoscorpion, Dinocheirus arizonensis (Banks), from the Sonoran Desert. Phylogenetic trees resolved two clades of D. arizonensis, one from mainland Sonora, Mexico and southern Arizona (clade I) and the other from the Baja California peninsula and southern Arizona (clade II). The two clades were separated by a mean genetic distance (d) of approximately 2.6%. Hierarchical analysis of molecular variance indicated highly significant population structuring in D. arizonensis (overall Phi(ST)=0.860; P<0.0001), with 80% of the genetic variation distributed among the two clades. Most pairwise comparisons of Phi(ST) among populations within each clade, however, were not significant. The results suggest that phoretic dispersal on vagile cactophilic insects such as the neriid cactus fly Odontoloxozus longicornis (Coquillett) provides sufficient gene flow to offset the accumulation of unique haplotypes within each clade of the non-vagile pseudoscorpion. Preliminary results on dispersal capability of O. longicornis were consistent with this conclusion. Tests designed to reconstruct demographic history from sequence data indicated that both clades of D. arizonensis, as well as O. longicornis, have experienced historical population expansions. Potential barriers to gene flow that may have led to genetic isolation and diversification in clades I and II of D. arizonensis are discussed.
authors.affiliation: Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Guaymas, Apartado Postal 284, Guaymas, Sonora 85480, Mexico. epfeiler@asu.edu
authors.forename: Edward
authors.initials: E
authors.lastname: Pfeiler
authors.forename: Ben G
authors.initials: BG
authors.lastname: Bitler
authors.forename: Sergio
authors.initials: S
authors.lastname: Castrezana
authors.forename: Luciano M
authors.initials: LM
authors.lastname: Matzkin
authors.forename: Therese A
authors.initials: TA
authors.lastname: Markow
mesh_terms: D000818:Animals; D001097:Arachnida / Q000145:classification / Q000235:genetics*; D001130:Arizona; D004272:DNA, Mitochondrial / Q000235:genetics; D003889:Desert Climate; D019143:Evolution, Molecular; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes; D008800:Mexico; D008957:Models, Genetic; D010802:Phylogeny; D011157:Population Dynamics; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial