GENETICS EXAM 2 QUESTIONS
AND THEIR REVIEWED ANSWERS
Fur color in a species of mouse is controlled by a
single gene pair. BB animals are black and bb animals
are while. Bb animals exhibit grey fur. What type of
interaction is shown by the two alleles in the
heterozyous animals.
incomplete dominance
What is penetrance?
the percentage of individuals having a particular genotype
who express the expected genotype.
In chickens, the dominant phenotype, Cr, produces
the creeper phenotype. The creeper allele is lethal in
the homozygous condition. The homozygous trait
results in a normal chicken. If two creepers are mated,
what is the phenotypic ratio among the living?
2 creepers: 1 normal
A boy has a blood type of MN with a genotype of
LmLn. His blood cells possess both M and N antigens.
What is the relationship between his two alleles?
codominance
A gene has 3 alleles. How many different genotypes
are possible at a locus in a diploid organism?
6
what type of gene action occurs when one gene
masks another gene at a different locus?
Epistatsis
, in humans, mitochondrial genetic disorders are
inherited from only the mother. The severity of these
diseases can vary greatly, even within a single family.
What form of inheritance does this show?
cytoplasmic inheritance
A man and woman are both deaf due to being
homozygous to a certain autosomal mutant allele.
However, they are homozygous recessive at a
different gene loci. If all their children have normal
hearing, what event occurs in each of the children?
complementation
A recessive mutant allele of an autosome gene in a
species of mouse results in a short tail in males when
homozygous. However, when homozygous in females,
there is no effect. What is this genetic phenomenon
called?
sex-limited characteristics
A gene whose expression is affected by the sex of the
transmitting parent demonstrates which of the
following events?
genomic inprinting
with genetic maternal effect, the genotype of an
individual is determined by which statement?
the nuclear genotype of the maternal parent
what is the phenomenon called when there is a
stronger or earlier of a genetic trait in succeeding
generations
anticipation
in a _______________, environmental factors can
produce a phenotype that is the same as a phenotype
produces by a genotype
AND THEIR REVIEWED ANSWERS
Fur color in a species of mouse is controlled by a
single gene pair. BB animals are black and bb animals
are while. Bb animals exhibit grey fur. What type of
interaction is shown by the two alleles in the
heterozyous animals.
incomplete dominance
What is penetrance?
the percentage of individuals having a particular genotype
who express the expected genotype.
In chickens, the dominant phenotype, Cr, produces
the creeper phenotype. The creeper allele is lethal in
the homozygous condition. The homozygous trait
results in a normal chicken. If two creepers are mated,
what is the phenotypic ratio among the living?
2 creepers: 1 normal
A boy has a blood type of MN with a genotype of
LmLn. His blood cells possess both M and N antigens.
What is the relationship between his two alleles?
codominance
A gene has 3 alleles. How many different genotypes
are possible at a locus in a diploid organism?
6
what type of gene action occurs when one gene
masks another gene at a different locus?
Epistatsis
, in humans, mitochondrial genetic disorders are
inherited from only the mother. The severity of these
diseases can vary greatly, even within a single family.
What form of inheritance does this show?
cytoplasmic inheritance
A man and woman are both deaf due to being
homozygous to a certain autosomal mutant allele.
However, they are homozygous recessive at a
different gene loci. If all their children have normal
hearing, what event occurs in each of the children?
complementation
A recessive mutant allele of an autosome gene in a
species of mouse results in a short tail in males when
homozygous. However, when homozygous in females,
there is no effect. What is this genetic phenomenon
called?
sex-limited characteristics
A gene whose expression is affected by the sex of the
transmitting parent demonstrates which of the
following events?
genomic inprinting
with genetic maternal effect, the genotype of an
individual is determined by which statement?
the nuclear genotype of the maternal parent
what is the phenomenon called when there is a
stronger or earlier of a genetic trait in succeeding
generations
anticipation
in a _______________, environmental factors can
produce a phenotype that is the same as a phenotype
produces by a genotype
