PPT 4 Flashcards
phenomenon in large
population when more than one wild type allele occur.
Genetic Polymorphism
altered pre-existing alleles cause by random mutation that occurs in the population.
Mutant Alleles
change the gene or the protein
encoded by a gene so that it gains a
new or abnormal function.
Gain-of-function mutations
change a protein such that the
mutant protein acts antagonistically
to the normal protein.
Dominant-negative mutations
- dominant mutant allele is a loss of-function allele.
- used to describe patterns of inheritance in which a
heterozygote (with one functional allele and one inactive allele) exhibits an
abnormal or disease phenotype
Haploinsufficiency
a situation
in which an allele that is expected to cause a particular
phenotype does not
incomplete penetrance
- The hybrid (heterozygous)
offspring displays a THIRD
phenotype.
incomplete dominance
Neither trait is completely
dominant, as a result, there
appears to be a blending
phenotype.
incomplete dominance
condition in which the
phenotype of a heterozygote is
intermediate between the
corresponding homozygous
individuals
incomplete dominance
interaction between
genes that are alleles
and result in the
heterozygous
individuals being
superior to either of
the homozygous
parents.
overdominance
occurs when both alleles are expressed equally in the phenotype of the heterozygote.
codominance
may exist in a population level, and
different individuals in the population may have
different pairs of these alleles.
multiple alleles/multiple allelism
The gene for this trait is inherited through the X chromosome.
sex-influenced and sex-limited traits
If an allele makes one of these genes nonfunctional,
or causes it to take on an abnormal, harmful activity,
it may be impossible to get a living organism with a
homozygous genotype.
lethal genes
- The multiple effects of a single gene on the phenotype of an organism is called
- occurs when the expression of a
single gene has two or more phenotypic effects
Pleiotropy
- Phenomenon that describes how the allelic variants of two different
genes affect a single trait. - can exhibit epistasis and complementation.
gene interaction
the interaction between genes is
antagonistic, such that one gene masks or interferes
with the expression of another.
epistasis
whenever a dominant allele conceals the expression of both
recessive and dominant alleles at other loci.
dominant epistasis
when the
recessive allele conceals the expressing.
recessive epistasis
when genes conceal other genes by suppression.
dominant inhibitory
There is a recessive allele concealing the expression of dominant alleles at two loci
duplicate recessive
there is a dominant allele concealing the expression of
recessive alleles at two loci.
duplicate dominant
prevalent alleles in a natural population
Wild Type
phenomenon in large
population when more than one wild type allele occur.
Genetic Polymorphism
