module 6 pt1 Flashcards
what is evolution
a change in allele frequencies in a population over time
what are mutations
random changed in DNA sequences overtime
what are the forms of mutations
substitutions
deletions
insertions
duplications
how can bacterial and archaea genetics exchange genes
horizontal gene transfer
what is wild type
the first one we study from nature
what is a mutant
a cell or virus derived from a wild type that carries a genotype change
what is the medium that allows you to differentiate between different variants of bacteria
macConkey differential media
what is a selectable mutation
easy to detect mutated cells
what is a non selective mutation
requires specific screening - they don’t really produce any noticeable changes
what is a spontaneous mutation
occurs without external intervention
what is an induced mutation
caused environmentally or deliberately
what is a point mutation
only one base pair changes
what is a silent mutation
it has no effect on the protein sequence
what is a nonsense mutation
substitutes a stop codon for an amino acid
what is a missense mutation
results in an amino acid substitution
what is an insertion or deletion mutation
results in a shift in the reading frame
what mutation can be lethal
frameshift mutations (insertion/deletions)
what are homologous genes
genes that all descended from a single ancestral gene - they tend to have similar nucleotide sequences
what are orthologs
homologous genes that share the same function
what are paralogs
single ancestral gene diverges to may different functions in many different organisms
what are gene duplications
thought to drive evolution of gene families and organisms
what occurs more often: insertions/duplications or deletions
deletions
what is evolutionary selection defined by
fitness
what is genetic drift?
random process that can cause gene frequencies to change over time (unpredictable change in the gene pool)
what does genetic drift usually result in
limited diversity
what is it called when a small group of individuals breaks away and forms their own population in a separate location?
newly founded population
when does the bottleneck effect occur
when a Radom event unselectively reduces the size of a population
how do organisms whose reproduction is asexual create genetic diversity?
horizontal gene transfer
what are the 3 mechanisms of horizontal gene transfer
transformation
transduction
conjugation
what is vertical gene transfer
inheritance from parental organisms
what is homologous recombination
process that results in a genetic exchange between homologous DNA from 2 sources
what is transformation
genetic transfer process by which free DNA is incorporated into a recipient cell and brings about genetic change
what is competence
a call that can take up DNA and be transformed
what is conjugation?
requires cell to cell contact
what F cell will be pulled toward what F cell
F- will be pulled towards F+
what are the F cells after combination
F+
which F cell is the donor cell
F+
what is an Hfr cell
high frequency of recombination cell ( has a chromosome with an inserted F plasmid)
how do Hfr cells transfer their information to another cell?
they form a pilus
whats the result of the F cells after Hfr conjugation
the F- cell does not become F+
what is transduction
transfer to DNA from one cell to another by bacteriophage
what is generalized transduction
DNA from any portion of the host genome is packaged inside the virion
what is specialized transduction
DNA from a specific region of the host chromosome is integrated directly into the virus genome
what are the two phases of generalized transduction
lytic cycle
transduction
what is the core genome
consists of genes shared by all the strains studies
what is the pan genome
the sum of the above core genome and the dispensable genome
not present in each thing
