Global phylogeography of the leatherback turtle (Dermochelys coriacea)

Abstract

Analyses of mitochondrial (mt) DNA control region sequences from 175 leatherback turtles Dermochelys coriacea from 10 nesting colonies revealed shallow phylogenetic structuring of maternal lineages on a global scale. Eleven haplotypes were observed, and mean estimated sequence divergence, p = 0.00581, is much lower than the deepest nodes reported in global mtDNA surveys of the green turtle Chelonia mydas, loggerhead Caretta caretta, and ridley turtles Lepidochelys spp. The leatherback turtle is the product of an evolutionary trajectory originating at least 100 million years ago, yet the intraspeci®c phylogeny recorded in mitochondrial lineages may trace back less than 900 000 years. The gene genealogy and global distribution of mtDNA haplotypes indicate that leatherbacks may have radiated from a narrow refugium, possibly in the Indian±Paci®c during the early Pleistocene glaciation. Analysis of haplotype frequencies revealed that nesting populations are strongly subdivided globally (F ST = 0.415), and within ocean basins (F ST = 0.203±0.253), despite the leatherback's highly migratory nature. Within the Atlantic signi®cant differences in haplotype frequency distributions and Nm values < 2 are observed in pairwise comparisons between St. Croix (U.S. Virgin Islands) and mainland Caribbean populations, and between Trinidad and the same mainland populations. These ®ndings provisionally support the natal homing hypothesis for leatherback turtles, although several proximal nesting populations were indistinguishable, suggesting recent colonization or less precise natal homing behaviour than documented for other marine turtle species. The evidence of natal homing, manifested on ecological time scales, may be erased in some populations by rapid rookery turnover resulting from climatic¯uctuation and the ephemeral nature of nesting habitat on a geological time scale. The evolutionary effective population size (N e ) is estimated from mtDNA data to be between 45 000 and 60 000, a value that exceeds current global census estimates of 26 000 to 43 000 adult females.

Effect of tidal overwash on the embryonic development of leatherback turtles in French Guiana

“…However, susceptibility to storm-related threats may vary according to species (Pike and Stiner, 2007); species with lower nest-site fidelity, such as leatherback turtles, would be less vulnerable than those with higher site fidelity (Lahanas et al, 1994;Dutton et al, 1999;Hatase et al, 2002). Moreover, highly dynamic and interseasonally variable nesting beaches in the Guianas (Plaziat and Augustinius, 2004), allow turtles to maintain successful nesting (Kelle et al, 2007), despite the fact that some beaches disappear between nesting years.…”

Geo-political genetics: Claiming the commons through species mapping

“…The elucidation of different haplotypes (or different ratios of haplotypes) from specific nesting rookeries of sea turtles is a powerful tool that has greatly increased our understanding of sea turtle biology and behavior. For instance, genetics data have proved a long-standing hypothesis that adult female sea turtles return to breed and lay eggs on or close to the beach where they were born, a process also known as natal homing (Meylan, Bowen, and Avise 1990;FitzSimmons et al 1997;Dutton et al 1999). Comparisons of haplotype diversity among sea turtle nesting assemblages has led to the conceptualization of different rookeries as independent management units (e.g.…”

Advances in the Application of Genetics in Marine Turtle Biology and Conservation

“…For example, population bottlenecks have been shown to have strong negative impacts on hatching success in endangered birds (Heber and Briskie, 2010), and low major histocompatibility complex (MHC) genetic variation in Tasmanian devils (Sarcophilus harrisii) contributes to a high susceptibility to deadly transmissible cancers (Jones et al, 2004;Siddle et al, 2010). Longevity and other life history traits of marine turtles provide buffers from diversity loss relative to other taxa (e.g., if depletion does not persist over several generations, some populations can recover quickly without necessarily losing genetic diversity; Dutton et al, 1999), but it may also make it challenging to detect. Early research suggested that contemporary genetic bottlenecks in small nesting populations of Mediterranean loggerheads could be mitigated by male-mediated gene flow (Carreras et al, 2007).…”