Exam 2 Flashcards
auxotroph
a mutant organism (especially a bacterium or fungus) that requires a particular additional nutrient which the normal strain does not.
episome
a genetic element inside some bacterial cells, especially the DNA of some bacteriophages, that can replicate independently of the host and also in association with a chromosome with which it becomes integrated.
merodiploid
A merodiploid is a partially diploid bacterium, which has its own chromosome complement and a chromosome fragment introduced by conjugation, transformation or transduction.
prototroph
Any microorganism that can synthesize its nutrients from inorganic material.
titer
((# plaques)(dilution))/volume
lysate
a preparation containing the products of lysis of cells.
complementation test
1st infection at high MOI - want 2 types in one cell –> mutant phenotype: mutation in the same gene
cotransduction
The simultaneous transduction of multiple genes, especially of two bacterial marker genes.
prophage
phage recombination
recombination test
1st infection at high MOI, 2nd infection low MOI to phenotype and genotype
pleiotropic allele
a single gene that controls more than one trait.
haploinsufficient
single copy of the wild-type allele at a locus in heterozygous combination with a variant allele is insufficient to produce the wild-type phenotype.
haplosufficient
only one working copy is necessary/sufficient for normal expression of the gene’s function.
heterokaryon
a cell (as in the mycelium of a fungus) that contains two or more genetically unlike nuclei.
penetrance
the extent to which a particular gene or set of genes is expressed in the phenotypes of individuals carrying it, measured by the proportion of carriers showing the characteristic phenotype.
saturated mutagenesis
a random mutagenesis technique used in protein engineering, in which a single codon or set of codons is substituted with all possible amino acids at the position.
multimeric enzyme
a protein composed of several subunits.
pleiotropy
the production by a single gene of two or more apparently unrelated effects.
Heritablility
F1/(F1+F2)
phenotypic variance
genetic variance + environmental variance
selective sweep
a process by which a new advantageous mutation eliminates or reduces variation in linked neutral sites as it increases in frequency in the population
MacDonald-Kreitman test
contrasts levels of polymorphism and divergence at neutral and functional sites and uses this contrast to estimate the fraction of substitutions at the functional sites that were driven to fixation by positive selection.
