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Professor of Biology
Office: 312 BBIowa City, IA 52242
Email: email@example.comWeb: More About Dr. Malone - Related Websites and Resources
BS, Chemistry, University of California-Los AngelesPhD, Molecular Biology, University of Oregon
Post Doctorate, Molecular Genetics, UNIV OF CHICAGO
Biosciences Graduate ProgramInterdisciplinary Graduate Program in GeneticsInterdisciplinary Graduate Program in Neuroscience
Chromosome behavior in meiosis
Chromosomes undergo several special events during meiosis, the process wherein chromosome number is reduced from diploid to haploid ( to form sperm, pollen, eggs, spores, etc.). The first unique chromosomal event is genetic recombination and homologous chromosome pairing. The second unique event, the reductional division, segregates the two paired homologous chromosomes to opposite poles. We are answering three major questions about chromosomes in meiosis utilizing genetics, molecular biology, microscopy, and protein biochemisty.
First, we are asking what makes a region of a chromosome a recombination hotspot. Some regions of chromosomes recombine at rates 10-20 fold higher than the average. We have cloned, sequenced, and manipulated such a hotspot region; at least two components are involved. One is the chromatin structure of the region (which extends over 20kb). We are beginning experiments to investigate how that structure is formed, and what proteins are important for its maintainance. A second component to the hotspot are local sequences at which the DNA is broken to form double strand breaks. We are deleting, substituting, moving, and manipulating these sequences in vitro, and replacing them in the chromosome in vivo to determine what is important.
Second, we are asking how meiotic recombination initiates. Specifically, we are asking how the 10-12 gene products required interact with each other to form an initiation complex; in concept this complex is analogous to the complexes that initiate DNA replication. We have begun to define interactions between proteins that are only made in meiosis, and whose only role is to initiate recombination by making breaks.
Third, we have discovered that the initiation of recombination somehow signals the reductional division so that it delays until the proper time. We have determined that 6 of the initiation genes are required for this signal. We are asking if all of the initiation functions are required for the signal, if their assembly on the chromatin is the signal, and how the signal is transduced to create the proper delay of the division. We are also looking for mutants that cannot carry out the proper communication between recombination initiation and the first division.
Date Last Modified: 08/04/2015 -
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