Testing the Utility of Mitochondrial Genome Rearrangements as Phylogenetic Markers in Ischnocera (Insecta:Phthiraptera)

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The methods by which genomic data are analyzed to construct phylogenetic trees are of vital significance in interpreting conclusions. Consequently, new methods of analysis need to be tested before they can be accepted. Dr. Cameron and his colleagues aim to test a range of proposed methods to infer evolutionary patterns from genomic data collected from numerous species of the largest suborder of lice, the Ischnocera, using variations (inversions, transpositions, losses or duplications) in the arrangement of genes. The test system is the mitochondrial genome of these lice. Mitochondria are the energy-producing portion of the cell, and their genomes are thousands of times smaller than the main nuclear genome, making it possible to sequence a large number of species and hence allowing comprehensive comparisons. Lice (Insecta: Phthiraptera) are a model system for studying mitochondrial genome evolution because they havethe fastest documented rate of genomic evolution with the largest numbers of gene rearrangements. This evolutionary speed makes it possible to draw a large amount of information out of a small number of species and to compare this information with evolutionary patterns deduced by other means (louse anatomy and gene sequences). The dataset which Cameron and colleagues will collect on louse mitochondrial genomes will provide empirical data on which analytical methods can be compared. This study will support a young postdoctoral investigator working in the laboratory of Prof. Whiting at Brigham Young University, in the emerging field of comparative genomics. Topics under study relate to basic biological questions such as how species evolve, how they diverge from one another, and how they develop new genes. This in turn has applications in medical research towards understanding the genetic basis of disease, particularly those affected by mutations in the mitochondrial genome. By studying genomes smaller and simpler than the nuclear genome, Dr. Cameron and his colleagues seek to extend the analytical foundations from which comparative genomics can grow.