LIFESCI 1 Lecture Notes - Lecture 13: Wolbachia, Hyperthermophile, Ecological Relationship
Document Summary
Instructor: tonya kane: molecular sequence can show how bacteria have evolved. Problems = gene sequences can change multiple times through history and erase any inherited molecular features from common ancestor. Horizontal gene transfer: 85% of all bacterial genomes have been transferred at least once. Result = bacteria can have divergent sequences and mistakenly be misplaced. Solution = look at small-subunit rrna genes (little evidence of horizontal transfer: molecular signatures can identify major groups of bacteria, but not order of groups. About 50 groups of bacteria are recognized. About 25/50 are not purely cultured (identified by cloning genes: because even distantly related bacteria can exchange genes = should abandon idea of species . Populations with same episodes of periodic selection = 1 species: no final definition of a species of bacteria. Proteobacteria: the most diverse of all bacterial groups w/ many similarities in rrna gene sequences, many have evolved intimate ecological relationships with eukaryotic organisms.
