My dissertation research explores the genetics of hybrid incompatibilities and, separately, the evolution of recombination rates in D. melanogaster and its sibling species.
In Chapter 1, I show that a hybrid lethality factor(s) in the pericentric heterochromatin of the D. mauritiana X chromosome, hybrid lethal on the X (hlx), is incompatible with a factor(s) in the same ∼26-kb autosomal region from both D. sechellia and D. simulans, Suppressor of hlx (Su[hlx] ). By combining genetic and phylogenetic information, I infer that hlx-Su(hlx) hybrid lethality is most likely caused by a derived-ancestral incompatibility.
In Chapter 2, I map a recessive factor to the pericentromeric heterochromatin of the X chromosome in D. simulans and D. mauritiana, heterochromatin hybrid lethal (hhl), that causes lethality in F1 hybrid females with D. melanogaster. Using small segments of the D. melanogaster X chromosome duplicated onto the Y chromosome, I then map a dominant factor that causes hybrid lethality to a small 24-gene region of the D. melanogaster X and provide evidence suggesting that it interacts with hhlmau.
In Chapter 3, I estimate crossover frequencies for seven segments that tile across the euchromatic length of the D. mauritiana X chromosome when introgressed into the genetic backgrounds of D. simulans and D. sechellia. My analyses suggest that both cis- and trans-acting factors contribute to differences in the genetic control of crossover frequencies on the X among the D. simulans clade species.
In Chapter 4, I perform an evolutionary screen of meiotic genes to identify potential candidate genes that might contribute to species differences in the rate of crossing over. I then use a transgenic approach to introduce the D. mauritiana allele of mei-218 into D. melanogaster flies homozygous for a loss-of-function mutation at mei-218 and ask if the D. mauritiana mei-218 allele produces a D. mauritiana-like map in otherwise D. melanogaster flies. I show that the highly divergent meiosis gene, mei-218, is responsible for most of the 1.55-fold phenotypic difference in genetic map length of chromosome 2 between D. melanogaster and D. mauritiana.
|Advisor:||Presgraves, Daven C.|
|Commitee:||Lambert, David, Orr, Allen, Wittkopp, Patricia|
|School:||University of Rochester|
|Department:||School of Arts and Sciences|
|School Location:||United States -- New York|
|Source:||DAI-B 73/09(E), Dissertation Abstracts International|
|Subjects:||Genetics, Evolution and Development|
|Keywords:||Postzygotic isolation, Recombination rates, Speciation|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be