Evolution Lecture No. 2: Origin Of Genetic Variation II
September 12 , 2012
-Genome duplication is phenomenon in which an organism receives a copy of all possible genetic
material (every gene). This results in much redundant genetic material and is a quite common process in
flowering plants. The existence of tetraploidy or greater is quite literally the mark of genome
duplication. It is the product of failed meiotic segregation of genetic material. In this circumstance, the
individual would be capable of self-fertilization, but would have difficulty fertilizing a 1n gamete.
Producing The Raw Material For Evolution:
-Point mutations – creates new alleles that may or may not function differently.
-Chromosome inversions – change gene order and reduce recombination.
-Gene duplication – creates redundant gene copies, which may evolve new functions.
-Genome duplication – vastly increases redundant gene copies and potential for evolution.
Antarctic Ice Fish:
-First discovered in 1929, the Antarctic ice fish was observed to be unusual in that inhabited extremely
cold temperatures and exhibited clear, transparent blood. Apparently, its plasma consisted of
dysfunctional erythrocytes and an antifreeze-like glycoprotein. This glycoprotein is very similar in
nucleotide sequence to the digestive enzyme trypsinogen.
-Through further investigation, it was revealed that the glycoprotein was in fact the result of a genome
duplication (quite common in fish) in which a copy of the trypsinogen sequence evolved a new anti-
-Marfan syndrome is a genetic disorder (the mutation of a single gene) of connective tissue, in which
patients experience heart problems and are phenotypically identified by their extremely long fingers.
Quantifying Mutation Rates:
-Mutation rates can be calculated according to the following equations:
Rate of mutation = # of mutations / locus (or single nucleotide site) / generation
Rate of mutation = # of mutations / genome / generation
-Popular methods for obtaining rates are population surveys and direct methods using molecular data. HIV Infection Pathway:
-An HIV virion (extracellular form) binds its surface protein to the host leucocyte’s CD-4 and coreceptor.
HIV’s RNA genome is synthesized into DNA by reverse transcriptase and integrated into the DNA
genome of the host cell. RNA polymerase of host cell transcribes spliced genetic material, which is later
translated into the new generation of assembled HIV virions in the cell. These new virions bud from the
cell’s membrane to continue the infection.
1. Extract DNA from blood and/or tissue sample.
2. Amplify the desired g