Research specialist
taka at email dot arizona dot edu
Ph. 520 626 1727
Office: BSW121
Evolution is driven by a variety of forces including selection, new mutations, drift, and draft. In the broadest terms possible, I am interested in developing theoretical models to address the relative importance of these factors.
Currently, I am performing mathematical population genetics on a scenario similar to that proposed by Haldane in his seminal 1957 paper, “The Cost of Natural Selection”. In this situation, a mutant allele is present in a population at low frequency but becomes beneficial after an environmental change: the famous case of Biston betularia is one biological scenario described by this process. In Haldane’s original study, the beneficial allele must then fix without incurring enough “load” to drive the population to extinction.
Since “load” is probably not limiting in real biological circumstances (Ewens 1970), we instead concern ourselves with the circumstances under which an environmental shift may lead to extinction when this shift decreases the fitness of the wild-type, but beneficial variants arise occasionally. To do so, we consider the probability that a new mutant establishes when present (a branching process problem) and the probability that it arrives in time to “save” the population. An additional concern is whether selection operates in a “hard” or “soft” fashion; ideally, we would like to permit the nature of selection to vary between these two extremes.
In a past life, I performed bioinformatic and comparative genomic analyses on 3′ UTRs in Saccharomyces with Jason Slepicka. Since 3′ UTR sequences are not really untranslated, but rather are translated in small amounts due to the occasional misreading of stop codons as sense, they constitute a form of mostly-cryptic variation; hence, they experience small levels of selection. One might therefore expect them to be preadapted (Masel 2006). Unfortunately, our most powerful result, the apparent conservation of backup stop codons shallow in the UTR, can be explained as an artifact of the properties of joint geometric probability mass functions, not a consequence of preadaptation. This work formed the bulk of my honors thesis (2009).
In yet another past life, I wrote columns for the Arizona Daily Wildcat. Two of my better columns are this one on intelligent design and this satirical piece.
In my spare time, I train (and will eventually compete) as a powerlifter, a pursuit at which I am decidedly mediocre. I am also occasionally active in the defense of evolutionary theory from critics.
I received my B.S. in ecology and evolutionary biology, mathematics, and physics from the University of Arizona in 2009 and will soon be starting my Ph.D at the Max Planck Institute for Developmental Biology in Tübingen.