The molecular phylogenetics of marine turtles

The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

The molecular phylogenetics of marine turtles

Advanced Search Abstract The leatherback sea turtle Dermochelys coriacea population that nests in Brazil is restricted to a few individuals, but high densities of pelagic individuals are observed along the southern and southeastern Brazilian coast. We investigated the diversity of the mitochondrial DNA mtDNA control region in order to understand the relationship between nesting and pelagic leatherbacks from Brazil and elsewhere.

The molecular phylogenetics of marine turtles

High-quality bp sequences were generated, analyzed, and compared with published data from worldwide populations. We detected the presence of shared haplotypes between nesting and pelagic aggregates from Brazil, as well as haplotypes shared with other nesting areas from the Atlantic and Pacific.

Furthermore, the use of longer control region sequences allowed the subdivision of the common Atlantic haplotype A into 3 different haplotypes A1, A3, and A4thus improving the resolution of mtDNA-based leatherback phylogeography.

The use of longer sequences partially supported a closer association between nesting and pelagic individuals from Brazil and pointed to a complex origin for the pelagic individuals in the Brazilian coast.

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The leatherback turtle Dermochelys coriacea is a pelagic marine species with a worldwide tropical and subtropical distribution. It is highly adapted for life in the open seas, feeding on jellyfish, salps, and other gelatinous organisms distributed in the water column Marquez Although small, the leatherback population shows an increasing trend in the annual number of nests: Furthermore, rare nesting leatherbacks have been observed in other places in Brazil Barata and Fabiano and leatherbacks are often seen along the Brazilian coast, with a higher concentration of individuals along the southern and southeastern coast Barata et al.

Population declines have been observed around the world, mainly in the Pacific and Indian Oceans, since the early s Chan and Liew ; Spotila et al.

The leatherback turtles can travel very large distances Pritchardreaching cold waters where no other marine reptile occurs Goff and Lien Current available information from tag returns and stranding records in the western Atlantic suggests that adults engage in routine migrations between boreal, temperate, and tropical waters, presumably to optimize both foraging and nesting opportunities Pritchard Sea turtles have been subjected to intensive studies with molecular markers for over a decade Avise and Bowen Genetic diversity data in sea turtles have already allowed the identification of complex phylogeographic patterns Bowen et al.

The molecular phylogenetics of marine turtles

The genetic identification of the origin of bycatch or nesting sea turtles is currently performed with mitochondrial DNA mtDNA sequence analyses in a global scale.

The published mtDNA sequences of leatherback turtles are restricted to very few populations. In this work, we aimed to describe the Brazilian nesting and pelagic D.

Our analyses allowed us to establish the relationship between nesting leatherbacks from Brazil and elsewhere, as well as to ascertain the origin of the pelagic aggregate individuals. Furthermore, the use of longer mtDNA control region sequences proved to be a valuable tool in obtaining more consistent genealogical relationships of mtDNA haplotypes and individuals of D.

Materials and Methods Samples were collected from nesting and pelagic leatherbacks in Brazil Figure 1. Biopsies from skin and other tissues were also collected from dead individuals found on beaches. Polymerase chain reaction PCR mixes of PCR products were further processed and sequenced as previously described Lara-Ruiz et al.

Some procedures were adopted in order to generate high-quality sequences, namely: Consensus sequences GenBank accession numbers: EF—EF were obtained after careful analyses with the softwares Phred v. Sequence divergence among different haplotypes was estimated through the software MEGA 3.

We also used the median joining MJ network analysis Bandelt et al. The origin of pelagic leatherbacks in the Brazilian coast was investigated by comparisons with different nesting populations found in the Atlantic and Pacific regions. We performed a mixed stock analysis MSA to estimate the relative contributions of different nesting colonies to the pelagic aggregate.

For comparison purposes, we also computed admixture coefficients from molecular data as implemented in Admix 2.

Only short haplotypes bp could be used in these analyses. We used 2 baseline stocks Atlantic and Indo-Pacific populations to run 2 MCMC chains of size1 chain per baseline stock with a starting point of 0.

The Brazilian pelagic aggregate composition was estimated from the mean of 2 chains after burn-in steps. Results and Discussion High-quality bp long sequences were generated and analyzed in 2 ways: Thus, the use of longer control region sequences clearly improved the resolution of mtDNA haplotypes.

Polymorphisms from positions to are also included in the bp haplotypes.Marine turtle mitogenome phylogenetics and evolution. Recent advances in DNA sequencing technologies have made more molecular markers available for turtle phylogenetics. M. Le, N.N.

Fitzsimmons, G. AmatoEvolutionary relationships of marine turtles: a molecular phylogeny based on nuclear and mitochondrial genes. Mol. .

Marine turtle mitogenome phylogenetics and evolution - ScienceDirect

J.G. Krenz et al. / Molecular Phylogenetics and Evolution 37 () – lack of phylogenetic resolution among deep nodes of a tree. Even so, no recent research has questioned the real-ity of the deepest recognized division within extant tur-.

PDF | On Sep 1, , Eugenia Naro-Maciel and others published Evolutionary relationships of marine turtles: A molecular phylogeny based . The position of turtles among amniotes remains in dispute, with morphological and molecular comparisons giving different results. Morphological analyses align turtles with either lizards and their relatives, or at the base of the reptile tree, whereas molecular analyses, including a recent study by.

Dutton PH, Davis SK, Guerra T, Owens D () Molecular phylogeny for marine turtles based on sequences of the ND4-Leucine tRNA and control regions of . Sequence-based molecular phylogenetics and phylogeography of the American box turtles (Terrapene spp.) with support from DNA barcoding.

A phylogenomic analysis of turtles - ScienceDirect