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2002
LSU-HHMI Summer Undergraduate Research Program |
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 Allan
Mirpuri (David Pollock, LSU Dept. of Biological Sciences)
Evolutionary Analysis of Cytochrome Oxidase I in Vertebrate
Mitochondrial Genomes
When vertebrate mitochondrial DNA (mtDNA) begins to replicate
at the primary site (OH), the heavy strand of DNA remains in
a single-stranded state for an extended amount of time. During
this time spent in a single-stranded state (DssH) many mutations
readily occur within the strand until it becomes double stranded
again. As a result, the complimentary mutation may not occur
on the other strand, causing the replication of the mtDNA to
result in two asymmetrical genomes.
To analyze the changes caused by these mutations, a large number
of vertebrate mitochondrial genomes must be evaluated in order
to determine the rates of substitution as we move along the
genome. Base-pair substitutions due to hydrolytic deamination
of cytosines are fairly common and appear to reach a maximal
level due to strand protection (Faith and Pollock 2002). In
this experiment, we examine the cytochrome-oxidase I (Cox I)
portion of the genome, located just before the origin of replication
of the light strand, in order to find out how quickly this substitution
rate will reach its maximal level.
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