MBB 342 Lecture Notes - Lecture 6: Phylogenetic Tree, Cladogenesis, Phylogenetics
18 Nov 2020
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Document Summary
Evolution: different components, systematics, trying to understand interrelationships between living things, taxonomy, the science of naming and classifying, phylogenetics, focuses on evolutionary relationship, cladistics, hypothesizing relationships between organisms/genes/proteins. Cladistics: 3 basic assumptions, any groups or organisms/genes/proteins are related by a common ancestor, basic assumption & fundamentant tenant of evo theory, bifurcating pattern of cladogenesis, controversial. Only ever splits off into 2 groups from one common ancestor, never more: change in characteristics occurs in linages over time. Jumps will occur: there is a general trend, but no smooth graph or time, we need better sampling, lots of undersampling occurring. Homologs: common origins (ancestrally related) but do not have to function exactly the same (although it can, different types, orthologs, produced by speciation, essentially the same gene, tend to have similar function, ex. 2 forms in 1 species: when this occurs people may assume its due to horizonatal gene transfer, however.
