Title

Natural selection and the evolution of the invasive trophoblast in hominoid primates

Defense Date

7-25-2006

Graduation Date

Fall 1-1-2006

Availability

Campus Only

Submission Type

thesis

Degree Name

MS

Department

Biological Sciences

School

Bayer School of Natural and Environmental Sciences

Committee Chair

Michael Jensen-Seaman

Committee Member

Brady A. Porter

Committee Member

David J. Lampe

Keywords

ECM, Evolution, Ka/Ks, MMP, Placenta, Reproduction, TIMP

Abstract

Humans and apes (hominoids) differ from Old World monkeys (OWMs) in the depth of placental trophoblast invasion. OWMs have a superficial placentation, with little invasion of the trophoblast into the uterine endometrium, while hominoids, and humans in particular, have a more invasive trophoblast, allowing for increased blood flow and nutrients to the developing fetus. This dramatic, morphological change, occurring on the hominoid stem branch and human lineage, may be explained by positive selection of genes involved in trophoblast implantation, resulting in the origin of the invasive trophoblast. Comparative sequencing of cell adhesion molecules, proteinases, and proteinase inhibitors involved in trophoblast implantation, in representative OWM and hominoid species, revealed uniform, purifying selection, with little differences between the hominoid stem branch, the human lineage, and the rest of the tree, suggesting that positive selection on these genes alone may not account for the phenotypic differences between humans and our primate relatives.

Format

PDF

Language

English

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