GE CLST 70B Lecture Notes - Lecture 8: Phylogenomics, Neontology, Molecular Clock
6 Feb 2017
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Gene trees do not always match species trees. Incomplete lineage sorting: building phylogeny based on one gene alone can lead to incorrect trees bc gene history often splits after a species splits. In order to make an accurate tree: use more than one gene, use math to model how dna evolves. Entire genomes can provide results with high confidence, but are very computationally intensive. Throw as much data as possible at the problem, let it solve itself. Phylogenomics: uses 100s of thousands of loci. Timing of phylogenetic question determines which data will be useful. Quickly evolving genes help us resolves more recent relationships. Microsatellite loci: some of the fastest-evolving genetic loci we know about. Slowly evolving genes help us resolve deep relationships. Cladogram: only the topology (pattern of splits) is informative: length of branch means nothing, probably every tree drawn by hand.
