Biology 1002B Lecture Notes - Lecture 23: Channelrhodopsin, Opsin, Volvox
11 Apr 2016
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The sequences in chlamy have evolved; this is exemplary of evoluion (change in gene sequence) Neutral theory of molecular evoluion: before we could compare protein sequence with nucleoide sequence, we thought that all mutaions/subsituions afect itness, either posiively or negaively (though mostly negaive: many mutaions actually have no efect on protein sequence. Volvox and chlamy have 17 diferences between them, but if you went back in ime, maybe there were only 3 diferences, and if you went ahead in ime, maybe there would be 30 diferences! Neutral mutaions occur at a constant rate over ime. For nonsynonymous mutaions, the likelihood that the mutaion is deleterious is quite high, so the organism won"t survive: for synonymous mutaions, the rate of survival is high because the protein sequence is not changed. Cytochrome c is constrained within the membrane; it can"t really evolve: if it changes too much, the enzyme will be killed and won"t work anymore.
