![]() Katie Peichel |
Associate Member, FHCRC Division of Human Biologycpeichel@fhcrc.org
Research Interests | Publications |
Research InterestsWhat is the genetic basis of variation between species? I first began to study this problem as a graduate student at Princeton, focusing on the vertebrate skeleton as a model system because of the incredible diversity in size, shape and number of skeletal elements in different species. These changes underlie many functional adaptations, such as swimming, flying, or walking upright on two legs. My graduate studies in Tom Vogt's lab focused on a mutation called Ulnaless that alters skeletal patterning in the limb, reminiscent of changes seen in the flippers of seals, where modifications in the size and shape of the ulna and radius in the forelimb are one of the adaptations for swimming. In order to identify the molecular basis of the Ulnaless mutation, I undertook a positional cloning approach and ultimately found that the Ulnaless mutation affected a cis-regulatory element necessary for limb specific expression of the HoxD genes.When I started a postdoc in David Kingsley's lab at Stanford, I wanted to know if the same types of genetic mechanisms identified in laboratory mutants were responsible for the evolution of skeletal morphologies in natural populations. Together, David and I developed a system to determine the number of genetic changes that control morphological and behavioral differences between species, to map the location of these changes, and to ultimately find the DNA sequence changes responsible for evolutionary modifications in vertebrates. We chose a small fish, the threespine stickleback (Gasterosteus aculeatus), as a model system, due to the incredible diversity of morphologies and behaviors in different freshwater populations, and the ability to cross different species of these recently evolved fish using artificial fertilization in the lab. I developed the first genetic linkage map for the threespine stickleback, and we have since used this map to identify genes that contribute to morphological evolution in natural populations. | |
| When I first began reading about sticklebacks, I was particularly excited about the possibility of using genetic approaches in these fish to study the evolution of behavior. Sticklebacks have some of the best-studied behaviors of any organism. There is incredible natural variation in many different behaviors (courtship, parental care, social aggregation, aggression, predator avoidance, spatial learning) in natural populations of sticklebacks. Current work in my own lab is focused on identifying the genetic and neural mechanisms that underlie the evolution of behaviors, particularly for those behavioral differences that contribute to reproductive isolation between overlapping populations of sticklebacks. Therefore, these studies will also lead to insights about the genetic mechanisms that contribute to the formation of new species. I am also interested in the evolution of sex determination, as life as a male or a female has profound impacts on the morphology, physiology and behavior of an organism. We have genetically defined a single major locus that determines male sex in threespine sticklebacks and found that this locus is on an evolving Y chromosome. We are currently working to identify the gene that controls sex determination in threespine sticklebacks. In addition, we are investigating the diverse mechanisms of sex determination found within the stickleback family to gain insight into the evolution of sex determining mechanisms and sex chromosomes. | |
Publications
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