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dc.contributor.advisorLangeland, James A., 1964-
dc.contributor.authorDekker, Robert G., II
dc.descriptionvi, 33 p.en_US
dc.description.abstractAs the most primitive extant vertebrates, lampreys occupy an important phylogenetic position in the study of evolution from non-vertebrate chordates to jawed vertebrates (gnathostomes). The Emx gene family is widespread and originally thought to only be involved in forebrain development, but expression seen in other areas suggests a more widespread role. Two copies of Emx exist in amphioxus and three copies exist in some gnathostomes. The study of Emx genes, their evolution and expression, can provide valuable information into the timing and consequences of gene duplication events in chordates. In the lamprey P. marin us it was shown that only one Emx gene existed. In this study we isolated a second Emx gene from lamprey that is sister to PmEmxA and orthologous to all other gnathostome Emx genes. Phylogenetic analysis of this novel Emx gene is not consistent with the 2R hypothesis, which states that the early vertebrate lineage underwent one or more complete genome duplications. Rather, this new gene suggests independent Emx duplication in lamprey. Analysis of this novel gene is compatible with the duplication-degeneration-complementation (DOC) model as our study suggests that duplicates of an ancestral Emx gene suffered regulatory element innovation allowing for complementary Emx subfunctionalization. In-situ hybridization reveals that this new Emx gene displays an expression pattern that differs both spatially and temporally from its homolog. PmEmxA appears to nest within PmEmxB expression in the pallial divisions of the forebrain, but exhibit complementary expression in the hypothalamus. These unique expression patterns suggests that innovations in regulatory elements following an EmxA/B ancestral gene duplication allowed for the apparent subfunctionalization of PmEmxB, thus supporting the DDC model.en_US
dc.publisherKalamazoo Collegeen_US
dc.relation.ispartofKalamazoo College Biology Senior Individualized Projects Collection
dc.relation.ispartofseriesSenior Individualized Projects. Biology;
dc.rightsU.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.
dc.titleA Novel Emx Gene in Pelromyzon marinus Offers Insight into the Timing and Consequences of Gene Duplication in the Chordate Lineageen_US
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  • Biology Senior Individualized Projects [1489]
    This collection includes Senior Individualized Projects (SIP's) completed in the Biology Department. Abstracts are generally available to the public, but PDF files are available only to current Kalamazoo College students, faculty, and staff.

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