Resolving Hydractiniidae and Hydroidolina Phylogeny Using Mitochondrial Genomes

Abstract

TThe proposed research will provide a set of 16 near complete mtDNA gene orders. The observed gene rearrangements will be used to investigate the phylogeny of the Sub-Class Hydroidolina and the Family Hydractiniidae. All the medusozoan classes contain a linear mitochondrial genome (mtDNA genome), whereas the Class Anthozoa contains a circular mtDNA genome (Bridge et al., 1992). The linear structure of the medusozoan mtDNA genomes is the most likely reason why these genomes are underrepresented, because the most rapid methods of mtDNA genome sequencing take advantage of the circular nature of most animal mtDNA. In a circular genome where mtDNA gene order is unknown prior to isolation, the forward and reverse primer(s) are designed based on the sequences of one or two highly conserved regions. Linear mtDNA requires a more involved approach, making it more difficult to sequence in its entirety than circular mtDNAs. In chapter 1, a novel assay to determine linear mtDNA gene orders is presented. In chapter 2, the near-complete mtDNA genome sequences are presented, as well as 7 near-complete mtDNA gene orders determined by the mtDNA gene order assay. These data are used to investigate relationships in the Family Hydractiniidae. Finally, in chapter 3, an additional 9 near complete mtDNA gene orders are used to explore relationships in the sub-class Hydroidolina. This study significantly increases the number of known near-complete mtDNA genomes, as well as their mtDNA.