Joseph A. Ross
 Joe Ross |
Graduate Research Associatejaross@u.washington.edu
Research Interests | Publications | |
Research InterestsI am currently a graduate student in the Molecular and Cellular Biology Program at the University of Washington. Since joining the Peichel Lab in 2003, I have been working on the evolution of sex chromosomes in sticklebacks.While some "old" sex chromosomes such as the human Y chromosome have been extensively characterized, very little is known about the initial stages of sex chromosome evolution. For example, a universal characteristic of evolved sex chromosomes is loss of recombination in the region containing the master sex-determining (MSD) gene. However, the mechanisms initiating and propagating this loss have not been identified because the signature of the forces initially shaping a sex chromosome are lost over time as the chromosome "degenerates". We employ the threespine stickleback fish, Gasterosteus aculeatus, as a model system in which to characterize a recently evolved sex chromosome. Over the last 20 Myr, five species of stickleback have diverged; some extant stickleback species employ XY or ZW genetic sex determination systems, implying that one or perhaps both of these systems have evolved during this 20 Myr period of divergence. Genetic linkage analysis was required to identify the presence of a Y chromosome in the threespine stickleback because the chromosomes in this species have been reported to be homomorphic, while the sister species G. wheatlandi, the black-spotted stickleback, has a cytogenetically visible Y chromosome. The threespine stickleback Y chromosome is an excellent model for the purpose of identifying the molecular and genetic characteristics of a young sex chromosome. | ||
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My current threespine stickleback research efforts include efforts to clone the non-recombining portion of the Y chromosome in order to identify the MSD gene and to perform cytogenetic techniques such as fluorescent in situ hybridization (FISH) with BAC clone probes in order to physically map the Y chromosome and compare it to the X to identify chromosome rearrangements that may have caused loss of homologous recombination and thereby accompanied sex chromosome evolution. I am also employing a comparative approach to understanding sex chromosome evolution. Our lab, along with collaborators, is mapping sex determination loci in the stickleback species, and I am using FISH to search for heteromorphic sex chromosome pairs and identify whether sex chromosome rearrangements accompany speciation events in these closely-related species. We are also using these techniques to address the possibility that the XY and ZW chromosome systems reported in different stickleback species are derived from the same ancestral chromosome pair. |
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Publications(containing C. Peichel as author since 2001)
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Page Last Updated: 13 August 2008
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