My general research interests include evolutionary genetics and genomics and developing novel techniques to study evolutionary processes. In the Evolutionary Ecology group I focus on studying the evolution of sex chromosomes. In particular I take advantage of the sex chromosome-autosome fusions that are found in a few species of stickleback fish. These neo-Y chromosomes still recombine with the X, which provides a unique opportunity to study the progression of recombination suppression, sexually antagonistic selection, and evolution of sex determining regions.
I also am developing tools to help answer an important question in evolutionary biology: what are the exact genetic changes that drive phenotypic changes? Many studies that map quantitative trait loci (QTL) fail to find the specific genes or mutations underlying phenotypic changes. Advances in genome editing technologies present an opportunity to change that trend. Our group and others have mapped several traits (schooling behavior, armor plates, neuromast number) to the Eda locus. To identify the causative mutations in this locus, I am developing techniques to use precise genome engineering to test specific polymorphisms for their role in these evolutionarily important phenotypes.
Josephson MP, Aliani R, Norris ML, Ochs ME, Gujar M, Lundquist EA (2017) The Caenorhabditis elegans NF2/Merlin molecule NFM-1 non-autonomously regulates neuroblast migration and interacts genetically with the guidance cue SLT-1/Slit. Genetics 205: 737-748. https://doi.org/10.1534/genetics.116.191957
Josephson MP, Miltner AM, Lundquist EA (2016) Non-autonomous roles of MAB-5/Hox and the secreted basement membrane molecule SPON-1/F-spondin in Caenorhabditis elegans neuronal migration. Genetics 203: 1747-1762. https://doi.org/10.1534/genetics.116.188367
Josephson MP, Chai Y, Ou G, Lundquist EA (2016) EGL-20/Wnt and MAB-5/Hox act sequentially to inhibit anterior migration of neuroblasts in C. elegans. PLoS ONE 11: e0148658. http://dx.doi.org/10.1371/journal.pone.0148658
Josephson MP, Sikkink LA, Penheiter AR, Burghardt TP, Ajtai K (2011) Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain. Biochemical and Biophysical Research Communications 416: 367-371. http://dx.doi.org/10.1016/j.bbrc.2011.11.044
Burghardt TP, Josephson MP, Ajtai K (2011) Single myosin cross-bridge orientation in cardiac papillary muscle detects lever-arm shear strain in transduction. Biochemistry 50: 7809-7821. http://pubs.acs.org/doi/full/10.1021/bi2008992