Evolution Flashcards
The start?
Anoxic conditions with anaerobic metabolism.
Chemolitotrophic - chemoorganotrophic - phototrophic
Ex. H2S + CO2 -> S
Then what?
The great oxidation event
H2O + CO2 -> CO2 + O2
The high reduction potential of O2/H2O couple which has provided higher energy yield and then higher reproduction.
Fe2+ + O2 –> Fe3+ ore
Stromatophiles?
Fossilized microbial formations
Tree of life?
Based on the 16S rRNA seqs where ~ 60 genes are shared
Mitochondria?
Alphaproteobacterium + prokaryote
Chloroplast?
Cyanobacterium into early eukaryot
In common?
Ribosomes, 16S rRNA seq and circular DNA
Horizontal gene transfer?
Benefical genes transfered rapidly in the early forms of life and traits became assigned to each group. Provided genetic, physiological and structural differences.
Genes from archae and bacteria provided translation, transcription and metabolic genes.
Hyphosesis?
Several endosymbiosis
Symbiogenesis
Hydrogen hyphosesis
RNA-processing?
RNA splicing and separation between ribosomes and nucleus
Evolution?
Change in allele frequence in a population that over time resulted in descent with modification.
Cause of genetic variation?
Mutation
Recombination
Selection
Genetic drift
Mutations?
Random change in DNA that accumulate over time and is the driving source of evolution as a source of natural variation.
A new trait can have a selective advantage if environment changes. Mutations still occur but the trait will dissapear since it is not favoured by selection.
Recombination?
Rejoining of parts of DNA that generates new combinations.
Selection?
Based on fitness and selects for the reproduction of those organisms with mutations that provide a higher fitness advantage.
Genetic drift?
Cause gene frequency to change over time. Evolution in the abscence of natural selection.
Bottleneck events?
Reduced population size that then regrows.
Strains?
Genetic subtype or variant of a microorganism, ex. E. coli.
Core or PAN or both?
Core genome -> shared by all strains of a species.
Pan genome –> Core and Pan genome but not shared by all strains of the organism. Acquired by horizontal gene transfer.
Systematics?
Polyphasic approach -> phylogenetic species concenpt
Why are there Differences in DNA?
Function of mutations that have accumulated since the strains shared a common ancestor.
Changes can be estimated homologous nuvleotide positions and then through seqs alignment.
Homoplasy?
Convergent evolution. Shared trait not from a common ancestor.
Phylogenetics concenpt?
Strains that share traits, cohesive genetic material and share a reason common ancestor
DNA-hybridization?
Probe and target DNA –> % of probes that hybridize to target DNA and similarity in ssu rRNA.
Difference @ species level?
ssu rRNA
RecA
GyrB
MLST?
Housekeeping genes with essential functions on the same chromosome. Similiar seq for a gene, allele number and 2 strains have the same allelic profile.
Genome fingerprinting?
Eva. between samples of a species
Polymorphism?
> 2 changes in differences of morphs or forms, even as phenotypes.
Ribotyping?
For identification of bacteria. As rRNA in a microbial genome have a high [] feature of all sums and bands.
Phenotypic analysis?
FAME -> between gram- bacteria
Proof-readers?
IJSEM - new taxa
ICDP - review
Summary?
Berkleys manual
The prokaryotes
