Lecture 20 Flashcards
HGT and Microbial Evolution (10 cards)
why do bacteria have more opportunities for evolution
they are very quick to divide and very numerous (millions to billions of bacteria per colony)
mitochondrial/ archaeal merger event
archaeal host cell formed a symbiotic relationship with a bacterium … gave rise to mitochondrian
huge to the origin of eukaryotes
how do we identify HGT events
comparative genomics
Endosymbiotic Theory
some of the organelles in eukaryotic cells were once prokaryotic microbes
HGT and evolutionary distance
decreases HGT likelihood
homologous recombination
mixing based on DNA similarity - results in shuffling
genetic recomb btw two similar / identical molecules of nucleic acids
HGT : long range transfer
gain of function
donor gene is not present in recipient … recipient incorporates the non-homologous gene
why do microbial species still exist then ?
- geographical isolation
- niche differentiation
(still shuffle within group - “quasi-sexual”)
long-range HGT still possible - unlike in macroorganisms
genome mosaics
a condition where an organism has multiple genetically distinct sets of cells
why is the tree of life considered a web
HGT
