Naming and Classifying Microbes Flashcards
taxonomy
-science of classifying/naming biological organisms
phylogeny
-study of the evolutionary relationships between different organisms
how do taxonomoists make classifications
-genotype, phenotype and phylogenetic information
what do microbes increasingly use to dictate taxonomy
-phylogeny less and less phenotype
taxonomy
domain = did
kingdom = king
phylum = phillip
class = come
order = over
family = for
genus = great
species = soup
who invented taxonomy
carl linnaeus
-created a system for classficiation to minimize chaos define structure to be used when new species are discovered
two names of an organism
-the genus and species
what do scientific names derive from
-may be descriptive of characteristics
-may honour a scientist
-might describe physical properties or appearance
logistics of scientific names and writing about them
-must be italicised of underlines
-genus is capatalized and species is lower case
-higher taxa are not italized they are captilized
-after the first use in a paper names are abbreviated with the first letter plus the species name
subspecies
-esssentially just the next finer classficiation after species
biovar
-grouping based on physiological or biochemical difference from other members of the species
serovar or serotype
-grouping based on surface antigens
other naming systems
-sometimes strains can be lumped together based on an important feature
strain
-genetic variant or subtype. often used to refer to a specific isolate - isolate a new strain give it a name to identify it
how does taxonomy help
-lumps together similar organisms with similar traits
-can allow us to communicate more effectiveky and to make educated gueses about newly discovered organisms
phylogenetic trees
-visual means of showing predicted evolutionary relationships between different organisms
how to compare phylogenetic relationships
-compare DNA sequences that are conserved amogst all organisms being compared
-more difference in DNA sequence = more evolutionary distance
-highly conswerved genes with a highly conserved function that accumulate mutations slowly over time
Determining phylogenetic relation SSU rRNA sequencing
-ribosome is conserved of all organisms on earth
-small subunit of ribosome is commonly sequenced to innfer phylogenetic relationships
-variable regions useful for identifying relationships
-conserved regions are useful for PCR
the woese tree of life
-iniversal tree of life based on nucleotide sequence similarity in rRNA
-genealogy of all life on earth
-established in the presence of three domains of life bacteria, archea, eukarya
16S rDNA to identify and classify bacteria
-isolate genomic DNA
-Use PCR primers that bind highly conserved regions of 16S rDNA
-PCR amplify and sequence 16S rDNA
-PCR remainder
how do you increase power of sequencing to build phylogenetic trees
-compare sequences of multiple conserved genes
phylogenetic trees limiations
-phylogenetic trees are predictions
-horizontal gene transfer can confuse things
-acquired DNA can undergo homologous recombination
-selective pressure causes mutations at different rates
