To get an idea of some of the research projects students work on during SSTP, I thought it’d be nice to highlight a few of the poster winners from 2013. Today, the spotlight is on the poster winners in the Judge’s Choice Category.
Noah Anderson (Dr. Manak)
The prickle (pk) gene was originally discovered in Drosophila as part of the planar cell polarity (PCP) pathway, responsible for coordinating the polarity of cells and their structures within the plane of a layer of cells. Interaction with other PCP proteins helps establish proper polarity, and mutations in PCP genes result in aberrant polarity phenotypes, most notably in hair patterning on structures such as the wing and leg. Drosophila have three isoforms of theprickle gene, two of which – pkpk (pk) and pksple sple (sple) – create distinct PCP patterns in the hair of the wing epithelium and bristles of the legs, respectively, when mutated (Gubb et al., 1999). However, mutation of both isoforms creates intermediary phenotypes in the wings and legs, suggesting that these two isoforms act in opposition to one another (Gubb et al., 1999; Lin & Gubb, 2009). Drosophila prickle is homologous to the human Pricklegene, which in recent years has been liked to epilepsy (Tao et al., 2011). One class of prickle mutants (pksple) are prone to epileptic seizures, while another class (pkpk mutants) are less prone to seizures compared to wild-type (Tao et al., 2011; unpublished data).
Laura Pang (Dr. Forbes)
The sunflower maggot, Strauzia longipennis, has been suspected to consist of multiple cryptic species. Morphological differences have appeared to indicate physical traits associated with genetic differences, thus taxonomic categorizations based on visual nuances split the species into two and later seven species (Lisowski, 1985; Steyskal, 1986; Stoltzfus, 1988). Further investigation utilizing mitochondrial DNA identifies 2 main haplotype groups (Axen et al., 2010). However, AFLP (Amplified Fragment Length Polymorphism) data of the S. longipennis nuclear genome suggest the existence of at least three clusters of genetically differentiated species (Forbes 2012). AFLPs are a valuable, but problematic markers, so we seek to find a different marker to differentiate species more easily. The ideal molecular marker should be selectively neutral and follow the rules of Mendelian inheritance in order to investigate patterns of gene flow and reproductive isolation (Selkoe 2006). Microsatellites, also known as simple sequence repeats (SSR) or short tandem repeats (STR), are tandem sequences of 2-6 nucleotides found throughout most metazoan genomes. They offer many advantages as genetic markers due to their co-dominance, allowing heterozygotes to be easily distinguished from homozygotes, and their high rates of polymorphism.