Gene Interaction Flashcards
what are the extensions/exception of Mendelian inheritance
sex linked traits
what is the difference between molecular basis of inheritance
-dominant and recessive have phenotypic basis
-dominance is determined by protein product of alleles
-phenotype is activity of protein products
haploinsufficient vs. haplosufficient
Haplosufficient: bot +/+ and +/m produce sufficient protein product for normal phenotype
Haploinsufficient: one dose of wild type(+/m) does not produce sufficient amounts of protein product for normal phenotype
mutant allele vs wild type
Wild type: found in nature(normal gene)
Mutant allele: mutation of the wild type gene producing a different phenotype
are wild type alleles typically dominant or recessive
dominant
two types of functional effects of mutant alleles
loss of function: decrease or total loss of functional gene product
gain of function: gene product gains new function or increases wild type activity
incomplete dominance vs co dominance
incomplete dominance: blending of both phenotypes
(red + white =pink)
codominance: both phenotypes are present
(red + white = red and white)
genotype and phenotype ratio of F2 for incomplete dominance
genotype: 1:2:1
phenotype: 1:2:1
genotype and phenotype ratio of F2 for codominance
genotype: 1:2:1
phenotype: 1:2:1
what is the genetic explanation for C-gene system for coat color of temp sensitive extremities (ex. Siamese cats)
the Ch allele which is a mutation from the natural C gene is a temperature-sensitive gene that is only functional at lower temperatures(like paws, ears, and tail), but lose catalytic function at higher temperature areas
what case can allow for dominant lethal alleles to persist in a population
late-onset genes that allow an affected individual to reproduce before affects begin to show
(ex. huntingtons)
what is pleiotropy? give an example
it is the alteration of multiple distinct traits through the mutation of a single gene
EX: sickle cell disease due to mutation in B-globin gene
epistasis definition
gene interaction resulting in altered phenotype
what 6 modifications can modify the 9:3:3:1 ratio?
complementary
duplicate
dominant
recessive epistasis
dominant epistasis
dominant supression
what can complementary analysis distinguish
-if mutations are on the same or different genes
-how many genes are responsible for mutations
penetrance vs. expressivity
penetrance: the percentage of individuals that show some degree of expression of a mutant genotype(ex you either have penetrance or you dont)
expressivity: the range of expression of mutant phenotype
(ex a spectrum of expresivity)
example for non-penetrance
-polydactyly (nonpenetrant 25-30% of the time)
-brachydactyly
duplicate gene interaction
-what is the phenotypic ratio
-what is occurring to change the ratio
-15:1
-dominant alleles are redundant at either locus. as long as one is present you will have the wild-type phenotype
dominant gene interaction
-what is the phenotypic ratio
-what is occurring to change the ratio
-9:6:1 dihybrid ratio
-2 genes contribute to a phenotype, homozygous dominant gives 1 phenotype(ex. disk), heterozygous gives another shape(ex. round), and homozygous recessive gives a third phenotype(e. elongated)
recessive epistasis
-what is the phenotypic ratio
-what is occurring to change the ratio
-9:6:1
-recessive allele at one locus will mask the phenotypic expression of the allele at the other locus
dominant epistasis
-what is the phenotypic ratio
-what is occurring to change the ratio
-12:3:1
-dominant allele at one locus overrides or masks the interaction of the other allele
dominant suppression
-what is the phenotypic ratio
-what is occurring to change the ratio
-13:3
-the second allele blocks expression of the first regardless of the firsts dominance
recessive suppressor
a mutant allele (the suppressor) reverses mutant affect of another gene resulting in a wild type phenotype
complementary gene interaction
-what is the phenotypic ratio
-what is occurring to change the ratio
-9:7
-genes work in tandem to produce a single product(both dominant alleles must be present for dominant trait)
how to determine with complementary analysis location of the genes
if wild type persists the mutations are on different genes
if mutant type persists mutant alleles are on the same gene
what does it mean to be penetrant
phenotype is consistent with genotype
