MICR 221 Lecture Notes - Lecture 16: Microbial Ecology, Transposable Element, Gc-Content

• School: Queen's University
• Department: Microbiology and Immunology
• Course: MICR 221
• Professor: Eric B Carstens

Document Summary

Ecosystems and environmental microbiology: microbial species, diversity and phylogeny, ecological analysis and microbial ecology, extremophiles and astrobiology, microbial species, diversity and phylogeny. Challenges to the definition of a species: horizontal gene transfer: in natural communities different microbes can interact and dna can be transferred to different species (both gram negative and gram positive) via transformation, transposable elements and bacteriophages. An e. coli genome shows that ~18% of its genes are from other species and in addition different e. coli strains can also show differences . Circular genome map of 2 e. coli genomes. Blue are sequences in common between 2 genomes. Hamburger ecoli compared to ecoli k12 (parent ecoli) If look at blue regions: regions where similar. Different colours (red and yellow): regions that differ. Other challenges to definitions of species e. g. 2. Work by ford doolittle (dalhousie u) dramatically underscores the importance of horizontal gene transfer to the tree of life. Have horizontal genome transfer from archaea to bacteria.