lecture 14 Flashcards
gene interactions pt.2
in what type of epistasis does must a precursor protein be converted into an intermediate protein by the first gene and the second gene converts the intermediate protein into the product?
double recessive epistasis
how many phenotypes occur in a double recessive epistatic dihybrid cross?
two
what is the phenotypic ratio of a double recessive epistatic dihybrid cross?
9:7
if one gene is recessive in a double recessive epistatic cross, what happens to the gene product?
it will not be made
what type of epistasis has one allele for a dominant trait that hides the phenotype of the other gene?
dominant epistasis
what is the phenotypic ratio of the dominant epistatic dihybrid heterozygote cross?
12:3:1
what happens if the dominant gene in a dominant epistatic relationship is homozygous recesssive?
the recessive gene will display its phenotype if it has a dominant allele
what happens if neither gene in a dominant epistatic relationship has a dominant allele?
the recessive phenotype is shown
what type of epistasis involves both genes being dominant with the protein products resulting in the same trait?
double dominant epistasis
what is the phenotypic ratio of the dihybrid heterozygote cross for a double dominant epistatic relationship?
15:1
what is the only way for the recessive phenotype to be shown in a double dominant epistatic relationship?
if both loci are homozygous recessive(e.g. aabb)
what type of epistasis involves a dominant allele at one locus producing the same phenotype as a recessive allele at another locus?
dominant recessive epistasis
what is the phenotypic ratio of the dihybrid heterozygote cross for a dominant recessive epistatic relationship?
13:3
what are the possible phenotypic ratios if there is only one gene involved?
1:2:1, 3:1, 2:1
what is the only way that the gene product is made in dominant recessive epistasis?
the first gene has a dominant allele and the second(inhibitory) gene is turned off(homozygous recessive)
