BIO 370 Lecture Notes - Lecture 19: Hiv, Influenza A Virus, Structure And Genome Of Hiv
One group of workers examined molecular evolution in the influenza A virus, and another
examined molecular evolution in the human immunodeficiency virus (HIV).
But synonymous substitutions do not always outpace nonsynonymous substitutions.
• Leitner and Albert studied two different regions of the HIV-1 genome.
– An internal structural protein (p17)
– An external protein involved with interactions with the immune system (the V3
loop region of viral envelope {covering} glycoprotein 120).
• Variation in structure of which protein might increase fitness of the virus?
This figure shows the proportion of nucleotide differences in (A) the p17 region of HIV-1 and (B)
the V3 region for pairs of strains plotted against the divergence time for each pair. What does
this show?
One would expect the neutral mutation rate n to vary among species as a function of
generation time; over any given time interval, more neutral mutations should occur in species
with short generation times.
However, at least some DNA and protein sequences appear to undergo clocklike change in
absolute time, independent of differences in generation time among species being compared.
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Document Summary
One group of workers examined molecular evolution in the influenza a virus, and another examined molecular evolution in the human immunodeficiency virus (hiv). But synonymous substitutions do not always outpace nonsynonymous substitutions. Leitner and albert studied two different regions of the hiv-1 genome. This figure shows the proportion of nucleotide differences in (a) the p17 region of hiv-1 and (b) the v3 region for pairs of strains plotted against the divergence time for each pair. One would expect the neutral mutation rate n to vary among species as a function of generation time; over any given time interval, more neutral mutations should occur in species with short generation times. However, at least some dna and protein sequences appear to undergo clocklike change in absolute time, independent of differences in generation time among species being compared. This figure shows the accumulation of neutral substitutions in mammals. Each point in this graph represents a pair of mammalian species.
