In addition to my research on Plasmodium mexicanum, I have been working with a few undergraduates (Max Ross, pictured, Leslie Barnard and Erin Keller) on a study of the population genetics of the sand fly Lutzomyia vexator, which transmits P. mexicanum. From studying the sand flies genes, we are hoping to answer these questions:
Understanding how mobile these insects are and how big their population is will hopefully help us determine explain the distribution of P. mexicanum and how frequently these flies might carry different strains between sites, which can effect the evolution of traits including sex ratio.
- Do sand flies frequently travel between sites?
- How many sand flies are there in the breeding population?
- How long has it been since these sand flies shared a common ancestor?
To answer these questions, we are looking at the sand flies' DNA. In particular, we're using regions of DNA called microsatellites that are very repetitive (e.g. ATATATATATAT) and as a result, they tend to get misaligned when they are being copied, creating new alleles that are a different length. In the figure to the right, you can see two individuals (top and bottom), each of which has alleles that are two different lengths. The individual on the top has one allele that is about 292 base pairs and one allele that is about 298 base pairs. As part of this project, we identified 8 microsatellite loci for this species!
Looking at how many different alleles there are in a population and how different the frequencies of alleles are between populations can give us an idea of population sizes and migration between sites.
With the help of Dr. Anne Vardo-Zalik (pictured, right) and 2 undergraduates (Megan Lind, pictured left, and Victoria Motz), we collected 173 flies sampled from four sites at the Hopland Research and Extension Center. We are now using the microsatellite loci mentioned above to analyze the samples. Check back soon for results!
This portion of my research is based on work supported by a Doctoral Dissertation Improvement Grant from the National Science Foundation (grant number 1310743). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.