Identifier

etd-0404103-140717

Degree

Doctor of Philosophy (PhD)

Department

Biological Sciences

Document Type

Dissertation

Abstract

Long INterspersed Elements (LINE or L1) have had an enormous influence on human genomic structure, comprising about 20% of the mass of the human genome. In this analysis the most recent L1 insertions in the human genome belonging to L1Hs Ta and preTa subfamilies were examined to further understand the impact L1 elements have had on human genomic structure and diversity. Collectively, over 800 human specific L1 elements from the draft sequence of the human genome were characterized. Estimates suggest that human specific L1 mobilization alone is responsible for increasing the size of the human genome by roughly 1.4 million bases, and that over 70 human specific L1 elements may still possess the ability to retrotranspose within human cells. Interestingly, over 35 L1 insertions were found adjacent to exons, though the majority of insertions showed general preference for gene poor regions of the genomes with low GC content. Analysis of over 500 L1 insertions by PCR on a diverse panel of humans representing geographically distinct human populations revealed that 115 (45%) of the Ta and 33 (14%) of the preTa human specific L1 insertions were variable in the human population with respect to insertion presence or absence. Sequence analysis of L1Hs Ta and preTa subfamily members yielded estimated average ages of 1.99 and 2.34 million years respectively. The 148 newly identified L1 insertion polymorphisms will serve as useful genetic markers for the study of human population genetics.

Date

2003

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Mark A. Batzer

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