Prepare this assignment according to the guidelines found in the APA Style Guide. An abstract is required. Mitochondrial DNA Use in Phylogenetic Studies Phylogenies obtained from molecular genetics are helpful in conservation biology for identification of evolutionary distinctiveness in endangered species. Turtles are presently one of the most endangered clade of vertebrates. The objective of this research was to present analyses of mitochondrial DNA data for four species of turtles in order to establish both species boundaries and the phylogenetic relationships between them. These are the Musk turtle (Sternotherus odoratus), the Northern map turtle (Graptemys geographica), the Blanding’s turtle (Emydoidea blandingii), and the Snapping turtle (Chelydra serpentine). These species are found in Ontario, Canada. Under the Species at Risk Legislation of Ontario, the Northern map and the Snapping turtles are species of Special Concern while the Blanding’s and the Musk turtles are threatened. The greatest risk for these species is being run over on roads and highways. Typically, turtles look for loose, sandy soils to lay their eggs in. But because exposed soil may be difficult to find in natural habitats, turtles are attracted to the artificially-created potential nesting sites such as shoulders of roads, railroad embankments, gravel drives and earthen dams. While they get to and from such locations, the turtles become vulnerable to both vehicular traffic and predators.

Genomes evolve as a result of continuous accumulation of mutations. This means that the amount of variation in nucleotide sequences in genomes indicates how recently those genomes have shared a common ancestor. If two genomes have diverged recently in the past, it is expected that they would have much fewer differences in their nucleotide sequences than two genomes whose mutual ancestor is more ancient (Tanaka & Aranishi 2013). Thus, by comparing several genomes, it is possible to figure out their evolutionary relationships. In most of the studies that use molecular markers, the predominant classes are mitochondrial DNA and microsatellite nuclear DNA. Mitochondrial DNA has an important advantage in all phylogenetic research because it is inherited from the maternal line (Chung 2013). This fact facilitates the monitoring of its transmission along the different phases, starting in the early evolution. Another advantage is that Mitochondrial DNA has a high level of variability and a high rate of mutation, compared with the nuclear DNA ( Rubinoff and Holland 2005), in spite of the fact that it does not encode the information for the synthesis of many proteins. This fact makes it ideal for the phylogenetic and phylogeographical studies. In determining the evolutionary course of primates, phylogenetic relationships and divergence times between species have been of particular interest to evolutionary biologists and anthropologists. Mitochondrial DNAs have often been used to investigate both the genetic relationships among closely related species and the genetic variability within primate species (Cai et al. 2013).

In this research, Mitochondrial DNA of four species of turtle was analyzed to determine their phylogeny. These were the Musk turtle (Sternotherus odoratus), the Northern map turtle (Graptemys geographica), the Blanding’s turtle (Emydoidea blandingii), and the Snapping turtle (Chelydra serpentine). From the Mitochondrial DNA analysis, the following phylogenetic tree was obtained.

Sn Mu – Musk turtle (Sternotherus odoratus)

Mu Bla MapSn – Snapping turtle (Chelydra serpentine)

Bla - Blanding’s turtle (Emydoidea blandingii)

Map - Northern map turtle (Graptemys geographica),

Phylogenetic tree showing the evolutionary relationship of four species of turtles

From the phylogenetic tree above, the Mitochondrial DNA analysis of the four species of turtles showed that the Musk turtle and the Snapping turtle appear to be closely related to one another than to the Blanding’s turtle and the Northern map turtle. Between the Blanding’s turtle and the Northern map turtle, the Blanding’s turtle appears to be the closest related to both the Musk turtle and the Snapping turtle. It may also be concluded that the Blanding’s turtle and the Northern map turtle are closely related to one another than to the Musk turtle and the Snapping turtle.

References

Cai, J., Y. Han., H. Ren., C. Chen., D. He., Lin Zhou., M. Eisner., D. Asico., A. Jose and Chunyu Zeng. 2013. Extracellular vesicle-mediated transfer of donor genomic DNA to recipient cells is a novel mechanism for genetic influence between cells. Journal Of Molecular Cell Biology 227

Chung, H. 2013. Phylogenetic analysis and characterization of mitochondrial DNA for Korean native cattle. Open Journal of Genetics 3 12-23

Rubinoff, D., B, S. Holland. 2005. Between Two Extremes: Mitochondrial DNA is neither the Panacea nor the Nemesis of Phylogenetic and Taxonomic Inference. ISSN: 1063-5157-238

Tanaka, T., F. Aranishi. 2013. Mitochondrial DNA Markers for PCR-Based Phylogenetic Analysis of Ark Shells.

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