A Survey of Arthropod Genomes in Search of a Reproductive Parasite
Click the Poster to View Full Screen, Right click to save image
John Loaisiga Mora
CoPIs:
Sam Charlie, Henry Hidalgo
College:
The Dorothy and George Hennings College of Science, Mathematics, and Technology
Major:
Biology
Faculty Research Advisor(s):
Jesus Ballesteros Chavez
Abstract:
Wolbachia is a genus of Gram-negative bacteria that is a common endosymbiont of various arthropods and it is known to affect the reproductive biology of their host. The diversity and prevalence of Wolbachia remain poorly understood; within the umbrella of a single species (W. pipientis) ten major lineages have been recognized defining discrete “super-groups”. Wolbachia has been found infecting diverse groups of animals, in particular Arthropods (insects, crustaceans, arachnids, and myriapods) and Nematodes (roundworms). Wolbachia is known to alter the reproductive biology of its host, causing cytoplasmic incompatibility, feminization, parthenogenesis, and male-killing. For this reason, there has been an interest in the potential of this parasite as a natural control agent against insects of medical or agricultural relevance, but this narrow focus has neglected other major lineages in their range of potential hosts such as the arachnids.
Beyond the potential applications, the study of this endosymbiont has also sparked interest in its role in the co-evolutionary history of the bacterium and their diverse host; in particular because Wolbachia transmits exclusively through the maternal line; comparable to the inheritance pattern of mitochondria.
Traditional characterization techniques of Wolbachia infections are laboratory intensive and show low sensitivity. This is partly due to the technical difficulties of isolation and cultivating the endosymbiont; which also impact traditional molecular PCR-based techniques for bacterial DNA sequencing. To date, three supergroups have been identified in the subphylum Chelicerata (the group that includes spiders, scorpions, and kin). But the spread and prevalence of Wolbachia among the broader lineages of terrestrial and aquatic chelicerates, besides a few spiders and scorpions, is largely unknown.
Here we develop and test a bioinformatic pipeline that leverages recent whole genome sequences (in the form of genomic reads) to identify and assemble reads matching the genetic signature of the presence of Wolbachia across diverse arthropod lineages.
We developed and tested custom Python scripts to (1) identify reads matching known Wolbachia sequences, (2) Assemble read into contigs, ideally representing a new whole genome assembly of Wolbachia, (3) quantify reads and coverage and (4) elucidate the identity and relatedness of the newly identified sequences among known strain of Wolbachia. Finally, we expect the combined analyses will reveal patterns of diversity host coevolution among a broader diversity of arthropods.