Complexities relating Genotype to Phenotype Flashcards
What is the wild type allele?
natural form go the allele
often dominant
functional protein
What is the mutant allele?
the mutation form
often recessive
often non-functional protein
What is incomplete dominance?
Heterozygotes shoe an intermediate phenotype
red x white = pink
phenotypes reflect the genotypes
What is the scale of dominance?
Dominance describes as a scale
one slightly more dominant than others
What is co-dominance?
Heterozygotes show the phenotype of both alleles
Expresses both of the different alleles they have
What do multiple alleles establish?
A dominance hierarchy
What is pleiotropy?
where one gene contributes to more than one trait
mutation affects both types of cell in different ways
may not seem related
What are lethal alleles?
a lethal combination of alleles
die in the uterus
can cause skewed phenotypic ratios
indicates an essential gene
2:1 ratio not 3:1
Example of sickle-cell syndrome
complications of dominance and pleiotropy
incomplete dominance on physiological level
co-dominance on a biochemical level
Gene combinations
rare for phenotype to be controlled by a single gene
all interact to give different phenotypes
What is epistasis?
gene interaction where the effects of an allele at one gene hide the effects of an allele at another gene
What are complementation tests?
Test to determine if a phenotype arises from mutation in same or separate genes
if the same both cause non-functioning enzymes
if crossed, then the same genes, offspring as they have non functioning enzyme
if crosses, different genes, offspring both inherit one functioning allele
What is penetrance?
measurement of the percent of individuals with given genotype who will exhibit phenotype associated with genotype
What is expressivity?
measures the extent to which a given genotype is expressed at the phenotypic level
What are the interactions between alleles of genes?
dominance
incomplete dominance
co-dominance
pleiotropy
lethal alleles
