Coding region polymorphism within the mitochondrial genome of horseshoe crab Limulus Polyphemus
Mentor:Christopher Chabot, Professor of Biology, Plymouth State University
Mitochondrial DNA is both unique to maternal lineage as well as susceptible to a higher mutation rate than nuclear DNA. This leads to polymorphic variation in the nucleotide sequence of mitochondrial genomes between individuals and populations. In order to determine polymorphic sites within the mitochondrial genome of Limulus polyphemus, a recently sequenced mitochondrial genome was compared to a mitochondrial genome from an unspecified population which was published to NCBI. This was accomplished by comparing coding regions of the two sequences using CLC Genomics Workbench 5 software. Results showed that median percent similarity of coding regions of the two mitochondrial genomes was found to be 97.8%, the average being 95.1%. Secondary structures of coding regions were analyzed and compared; specific to tRNAs, none of the mutated residues caused changes to the anticodon sites. Additionally, the tRNA secondary structures are highly similar between the two fully sequenced L. polyphemus mitochondrial genomes. Future work includes analyzing sequential differences in proteins and ribosomal subunits encoded by the mitochondrial genomes. Overall, this research reveals a fair amount of polymorphism within the coding regions of the mitochondrial genome while function inferred by secondary structure is generally retained.