exam 2 Flashcards
(29 cards)
what are the exceptions of mendelian genetics
incomplete and codominance
multiple alleles-polymorphism
epistasis
x-linked inheritance
what is meant by wild type
the norm- doesnt have to be dominant or recessive
what is meant by mutant allele
modified genetic information, italic letter
what is the threshold effect
normal phenotypic expression occurs whenever a certain level of gene product is produced
what is albinism
recessive loss of function in both locus - CaCa
what would a white cat with pigmented eyes mean
autosomal dominant mutation- melanocytes failed to migrate during development
what are the most often results in Gain-of-function
oppose wild type function- dominant negative
what is an example of gain-of-function mutations
proto-oncogenes, uncontrolled cell growth
what is incomplete or partial dominance
phenotype of heterozygote is intermediate to phenotypes of homozygotes
genotypic and phenotypic ratio for incomplete dominance
1:2:1
in what extension of mendelian genetics is there no dominance, fir instance it would just be R1 and R2
incomplete or partial dominance
explain incomplete dominance in terms of red flowers
red flowers are the wild type allele
white color -loss of function allele= no synthesis of red pigment
pink color- 1/2 the amount of red pigment produced
difference between complete dominance and incomplete dominance
incomplete- wild-type gene product is not sufficient for normal phenotype
how to tell difference between codominance and incomplete
incomplete dominance is going to have a variation. “The more copies of S an individual has, the more white fur appears, suggesting a dosage effect, which is a hallmark of incomplete dominance rather than codominance.” can gradually chance with number of alleles.
what is dominant epistasis in a nutshell
if an animal has just one copy of the hiding gene, it will completely cover up the rest. Big eraser- one is enough to erase all the others from phenotype
recessive epistasis in a nutshell
for the hiding gene to work it needs 2 copies to turn off a pattern
what is codominance
2 alleles of a single gene produce 2 distinct, detectable gene products
EQUAL
what is bombay phenotype
those that do not have the H substance antigen for A, B, or O phenotype
recessive lethal allele
can be dominant or recessive but must be HOMOZYGOUS for individual to be lethal
what is a dominant lethal allele
presence of one dominant allele will kill you eventually- HH and Hh have the same phenotype
why is AB blood type codominant
half and half- both showed EVENLY
how to know that you are dealing with 2 genes even though you are looking at one phenotype
ratio expresses in 16 parts
what is the phenotypic ratio of recessive epistasis
9:3:4
dominant epistasis phenotypic ratio
12:3:1
