The origins, evolution, and functions of lineage-specific genes in Drosophila Public Deposited

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  • March 21, 2019
  • Reinhardt, Josephine A.
    • Affiliation: College of Arts and Sciences, Department of Biology
  • To understand how species evolve and adapt to their environments, we must understand the nature of the genetic variation causing differences between and within species. Recent studies have identified entire genes that are unique to a single species (lineage-specific genes), but little is yet known about how these genes originate or function. Here I present the results of a number of studies of lineage-specific genes in a model organism, the fruit fly, Drosophila melanogaster. First (Chapter two), I show that even within species, genes can greatly expand or contract in size demonstrating that novel protein domains are segregating even within a species. Secondly (Chapter three), I show that two genes that appeared to be newly evolved and lineage specific are actually rapidly evolving, and surprisingly are essential. Finally, I find that a number of genes that arose recently from non-coding sequence (de novo genes) are diverse in their apparent mechanism of origin, but are surprisingly similar in their gene expression pattern and functions (Chapters four and five). Like the two rapid evolving genes, the de novo genes I studied appear to contribute to an essential function, as their loss causes lethality. This work represents the widest molecular screen for the function of lineage-specific genes yet attempted, and reveals surprising functional similarities between these novel genes despite their diverse evolutionary origins.
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  • ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biology.
  • Burch, Christina L.
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  • University of North Carolina at Chapel Hill

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