BIO 3102 Lecture 7: Lec 7 - molecular clocks
7 Apr 2017
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Lec 7 molecular clocks - mid 1 ends. High gc content, protein sequences (miss syn mutations), microrna"s syn sub can influence gene transcription (would miss all this). Highly repetitive short sequences, will find spurious matches. Super distant organisms - use protein sequence bc higher probability of matches and saturation of synonymous sites. Only so many synonymous codons so changes will be seen (if very distant) so will run out of options for each site and will not be helpful if cant align anything or track changes. Protein seq will have a higher likelihood that you"ll see changes that mean something. Influences: rates of replication errors, recombination/ rates of repair/ (= biochemical properties of repair enzymes) Life history of a specie, environmental factors, generation time. Rate of mutation and relative influence of genetic drift/selection (purifying or positive) Between different parts of the gene (5" utr vs exon) Between different sites of the protein (i. e active sites/allosteric sites - more functionally constrained)
