Exam #2 Flashcards
Multiple Alleles
presence of two or more alleles at a locus group.
ex- bloodgroup system
Antigen
any substance that can induce the production of an antibody
gene interaction
- occurs when genes at two or more loci work together to determine a single phenotype.
- one phenotype can be controlled by alleles of two different genes.
Epistasis
- special form of gene interaction
- the genotype at one locus masks the expression of the genotype at a second locus
types of epistasis
recessive, dominant, duplicate recessive, duplicate dominant, duplicate interaction, dominant and recessive, and none.
epistatic gene
gene doing the masking
hypostatic gene
gene being masked
recessive epistasis
there is a recessive allele but when it has a pair making it homozygous recessive, it doesn’t matter what the other pair is, this one will mask the other allele. it does have to be the specific allele of the pair at the loci.
9-3-4
ex- coat color in labs, or O blood type
dominant epistasis
only a single copy of the allele is needed to mask the other allele.
12-3-1
ex- squash color
duplicate recessive epistasis
if you have a pair of homozygous alleles it masks the other. It doesn’t have to be a specific one. it can be a or b.
9-7
ex-snails
duplicate dominant epistasis
15-1
dominant allele masks all the recessive alleles. At either loci.
the one comes from both aabb alleles.
sex influenced
displayed differently in each sex ex-beards in goats= heterozygote male= beard heterozygote female=no beard AUTOSOMAL GENES
sex limited
only occurs in one sex.
AUTOSOMAL
conditional alleles
show an extreme influence of environment on phenotype
ex-PKU and diet
conditional mutant
only expressed at certain environmental conditions
ex- wild type @low temp
mutant @high temp
discontinuous traits
exhibit only a few easily distinguished phenotypes
-qualitative
ex- seed shape= either round or wrinkled
continuous traits
displays a large number of possible phenotypes that are not easily distinguished.
-quantitative
ex- human height
