BIOL 2303 Lecture Notes - Lecture 8: Aliivibrio Fischeri, Metagenomics, Proteobacteria
21 Mar 2016
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Document Summary
New genes come from gene duplication and horizontal transfer. A single genome may contain multiple copies of a gene. Copies are not necessarily identical, just closely related. These copies have arisen from the duplication of an ancestral gene. Some cases, one copy evolves a new function. In other cases, ancestral copy had two functions. Each duplicate retains one of the original functions and retains a single function. Multiple copies of the hemoglobin gene: alpha, beta, delta, gamma. Evidence for specialization of different subunits to different developmental stages (ex/ gamma-hemoglobin is only used in fetus because it has a higher oxygen affinity) Neo-functionalization if 1 gene copy produces 2 gene copies, one with a new role and one with the old role. Sub-functionalization if the ancestral gene had two roles and the duplicated genes only have one of the roles. Paralogs: gene duplicates within the same species/genome.
