MICR 221 Lecture Notes - Lecture 13: Horizontal Gene Transfer, Ford Doolittle, Dna Microarray

• School: Queen's University
• Department: Microbiology and Immunology
• Course: MICR 221
• Professor: Virginia K Walker

Document Summary

Microbes including prokaryotes: often defined in terms of dna sequence identity, (e. g. > 97% for ~1500 bp in a particular gene) but there are still debates on the definition of a species in these groups. 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: happens not only in lab but in real world too. This dna history can be revealed by gc content* or by genome sequencing and analysis e. g. 1. 446) diagram of circular genome: same species with quite different genome, picked up quite different genes e. g. 2. Feb 2014: news item ford doolittle wins canada"s top science prize horizontal gene transfer. Other challenges to the definition of a species: Divergence through mutation & natural selection- random mutation (about 1/million bp during replication in prokaryotes). This dna history can also be revealed by genome sequencing.