Intellectual Merit: Centromeres are the site on every chromosome of mammals where kinetochore assembly and spindle attachment occur during cell division. Faithful segregation of every chromosome relies on the proper functioning of centromeres, and errors in the cascade of events prior to and after spindle attachment lead to chromosome loss - a disastrous genetic fate. This research aims to understand the functional modules found within mammalian centromeres. A genetic process called molecular drive is thought to account for the observation that the DNA found at centromeres across all individuals within one species is highly similar, whereas a counter process called genetic conflict may be responsible for the observation that vastly different centromere satellite sequence suites are found between species. Accordingly, as satellite DNA arrays expand on a chromosome, they can attract more microtubules during female meiosis and lead to unequal transmission of one parental chromosome over the other. In a recently proposed model, this process, called Centromere Drive, results in the rapid evolution of centromere binding proteins selected to equalize the transmission of each chromosome during meiosis, ensuring all chromosomes are inherited equally in a population. Current models of centromere evolution and predict that different, but closely related species within a given species group would experience shifts and expansions of satellite sequences that would result in species-specific satellite sequences at centromeres. The well-documented evolutionary history of species of kangaroos and wallabies, along with the known history of the evolution of their chromosome complements, provides an ideal opportunity to test the Centromere Drive hypothesis directly, as opposed to the inferential studies that currently support this theory. In doing so, the functional components of centromeres that facilitate equal chromosome segregation will be uncovered. This project will determine whether satellite DNA interacting proteins evolve in concert with satellite sequence suites, as predicted by centromere drive, or with species divergence, as predicted by centromere drift and molecular drive. Inherent to this research will be efforts to determine whether the proposed conflict driven evolution of these components are responsible for hybrid incompatibilities and which components in the cell are the subject of drive.
Broader impacts: This research involves a broad range of participants, including visiting faculty, post-graduate, undergraduate and high school students from a variety of socioeconomic backgrounds in the New York, Connecticut, Massachusetts and Rhode Island area. Undergraduate independent study students and high school students enrolled in the UConn Mentor Connection will be active participants throughout this research. Moreover, this research will serve as the foundation for development of three modular-format courses to provide training in utilization of massively parallel sequencing technology, which has revolutionized genome biology, but remains largely inaccessible to the individual scientist. Students will learn to prepare a library for sequencing, perform sequencing on the SOLiD sequencing platform and use bioinformatics to analyze the resulting data. The course will be open to advanced undergraduates, graduate students, postdocs and visiting high school teachers as part of the Professional Science Masters program in the Center for Applied Genetics and Technology. The inclusion of high school teachers as participants is part of the broader goals of this research in empowering educators to train both future generations of scientists as well as the future nonscientist members of the general public that will be directly impacted by shifts in genomic technologies.
