Stephan C. BaehrGraduate Student
Biology B.S., University of Utah 2014
1. What is the ultimate DNA mutational load of somatic tissues, and to what extent do these mutations contribute to measurable phenotypes? Surprisingly, while it is generally known that most mutations are what we consider harmful, and the effect of their accumulation is directly measurable across generations, the relative importance of DNA mutation accumulation is unknown in somatic tissues of a single individual. Or in other words, how bad specifically is the somatic accumulation of DNA mutations, how frequently are they arising? To what extent are they correlated with ageing phenotypes? The mutation rate of DNA is not a constant throughout the tree of life, and indeed, evidence even suggests that DNA mutation rates are not constant between human germline and human somatic cells. The rate and molecular spectrum of the mutation rate of somatic tissues has not yet been directly measured in any organism, due to several significant technical hurdles: technical hurdles that have recently become surmountable. Directly measuring the somatic mutation rate will contribute to our understanding of how our bodies change over time.
2. Variation within populations is a recurring theme in biology, and I am trying to better understand as-yet unexplained dynamics. “Populations” is usually meant to refer to groups of individual organisms, but it can also mean populations of cells within an organism, and even populations of organelles (mitochondria) within a cell. Effective population size, strength of selection, frequency and duration of selective forces, this is evolutionary analysis; but it is potentially even more, with regard to the fidelity of how information is stored over time, and how that information recapitulates non-mendelian (complex) phenotypes.
3. Daphnia are a model organism that in phenotypic traits is somewhat of a midpoint in complexity between C. elegans and D.melanogaster. In anticipation of increased interest in organisms of intermediate complexity between the two, I am transposing Drosophila CRISPR tools to Daphnia pulex to help ease the experimental burden of future investigators, as well as further answer my own questions about the burden of somatic mutation.