topic 3 Flashcards
what are the causes for mutant dominance
haploinsufficiency and dominant negative
haploinsufficiency vs dominant negative
haploinsufficiency is when one copy of the wildtype allele is not enough to produce a wildtype phenotype
a dominant negative is when the mutant interferes with a protein by binding to it and interfering with its functions so wildtype phenotype isn’t expressed “spoiler proteins”
an allele capable of causing death is called
lethal allele
what genes are those that without them the organism dies
essential genes
what is a pleiotropic allele
allele that affects several properties of an organism
what is penetrance
percentage of individuals with a given allele who express that allele phenotype
what is expressivity
the intensity of the phenotype being expressed by the allele (severity of phenotype)
what is the one-gene-one-enzyme hypothesis and how was it refined
one gene controls one specific enzyme and it was refined to one-gene-one-polypeptide where one gene controls one polypeptide
what is being tested in a complementation test
whether two mutations belong on the same gene
what is recessive epistasis
the double mutant phenotype shows pheno of only one mutation and has a ratio of 9:3:4
what do you call the single mutation that has the same phenotype as the double mutation
epistatic
what do you call the single mutation that is not expressed in the double mutation
hypostatic
what do you call it when a mutant allele of one gene masks the expression of a mutant allele of another gene and expresses its own phenotype instead
epistasis
what has a 9:7 ratio
a double mutation where the both single mutations have the same phenotype as the double mutant
what has a 9:3:4 ratio
a recessive epistasis where the double mutation only expresses the phenotype of one of the single mutations
what has a 12:3:1 ratio
a dominant epistasis where a dominant allele displays epistasis
what is a suppressor
a mutant allele that reverses the effect of a mutation of another gene
what has a 13:3 ratio
a scenario where a double mutation results in wild-type because one mutation masks the other (suppressor has no phenotype)
what has a 9:3:3 ratio
a synthetic lethal where the double mutant is lethal
what has a 14:2 ratio
suppressor is like mutant
what phenotypic ratio do lethal alleles lead to?
9:3:3 because 1 wouldn’t exist bc organism would die
what do you call it when some organisms with a certain gene does not display the phenotype
incomplete penetrance
how do you explain scenarios where someone has the trait of a dominant disorder but will never develop symptoms
incomplete penetrance
what is kind if trait is needed to be able to perform a complementation test
recessive single gene
