MCDB 2150 (Exam 4) Questions and
Answers
Gene interaction - Correct Answers -The idea that several genes influence a particular
characteristic.
Epigenesis - Correct Answers -The idea that an organ or an organism arise through the
sequential and development of new structures.
Mutations that interrupt many steps of ear development lead to - Correct Answers -
Hereditary deafness
Heterogenous trait - Correct Answers -A trait that can arise from a mutation in any
number of different genes. (many genes interact)
Hardy Weinberg logic - Correct Answers -Allele frequency:
-If you know one frequency you know the other (p+q=1)
Genotype frequency:
-If the homozygous recessive phenotype is obvious, you can count those individuals,
assume their genotype is aa, set aa equal to q2, and solve for q (p^2+2pq+q^2=1)
Genetic drift - Correct Answers -Change in the gene pool due to sudden population
shrinkage.
Gene flow (Migration) - Correct Answers -Genetic exchange due to the migration of
fertile individuals or gametes between populations.
Non-random mating - Correct Answers -Mates are chosen on the basis of the best
traits.
Mutations - Correct Answers -Produce genetic variation
Complementation tests - Correct Answers -Determine if mutations that cause the same
phenotype are in the same or different genes.
Epistasis - Correct Answers -When the expression of one gene masks or modifies the
expression of a gene or a gene pair.
-One gene can mask the phenotypic effects of another gene (eg. Baldness is epistatic
to blondness)
, Complementation - Correct Answers -Mutations are in two different genes.
-Two parents with "mutant" produce normal progeny.
-Happens because parents have defects in two DIFFERENT genes.
No complementation - Correct Answers -Mutations in the same gene.
Complementation analysis - Correct Answers -Allows us to determine whether two such
mutations are in the same gene.
Recessive epistasis - Correct Answers -Two or more genes can both be involved in
producing a particular phenotype.
Extranuclear inheritance - Correct Answers -Transmission of traits by genetic
information contained in cytoplasmic organelles such as mitochondria and cytoplasts.
Cytoplasmic inheritance - Correct Answers -Ex. mitochondrial inheritance:
Mitochondria have their own DNA.
•small circle of DNA with 37 genes.
-These genes function in energy production and protein assembly.
•Mitochondria are only passed along from the MOTHER.
Mitochondrial inheritance - Correct Answers --Passed from affected mothers to all
offspring•Affected fathers do not pass on the trait.
-Severity frequently related to the proportion of mutant mitochondria inherited at birth.
Maternal effect - Correct Answers -Genes are inherited from both parents, but the
phenotype of the offspringis determined by the genotype of the mother.
Loss of function mutation - Correct Answers --m/+ has normal phenotype
-reduces or eliminates the function of a gene product
Gain of function mutation - Correct Answers --m/+ has a mutant phenotype
-almost always dominant
-gene product has an enhanced, negative or new function
-change in regulation so gene is expressed at new time or in new location
A change in one base-pair to another in a DNA molecule is known as - Correct Answers
-A point mutation or a base substitution
Point mutation - Correct Answers -A mutation that can be mapped to a single locus.
Base substitution - Correct Answers -A single base change that produces a mutation.
Answers
Gene interaction - Correct Answers -The idea that several genes influence a particular
characteristic.
Epigenesis - Correct Answers -The idea that an organ or an organism arise through the
sequential and development of new structures.
Mutations that interrupt many steps of ear development lead to - Correct Answers -
Hereditary deafness
Heterogenous trait - Correct Answers -A trait that can arise from a mutation in any
number of different genes. (many genes interact)
Hardy Weinberg logic - Correct Answers -Allele frequency:
-If you know one frequency you know the other (p+q=1)
Genotype frequency:
-If the homozygous recessive phenotype is obvious, you can count those individuals,
assume their genotype is aa, set aa equal to q2, and solve for q (p^2+2pq+q^2=1)
Genetic drift - Correct Answers -Change in the gene pool due to sudden population
shrinkage.
Gene flow (Migration) - Correct Answers -Genetic exchange due to the migration of
fertile individuals or gametes between populations.
Non-random mating - Correct Answers -Mates are chosen on the basis of the best
traits.
Mutations - Correct Answers -Produce genetic variation
Complementation tests - Correct Answers -Determine if mutations that cause the same
phenotype are in the same or different genes.
Epistasis - Correct Answers -When the expression of one gene masks or modifies the
expression of a gene or a gene pair.
-One gene can mask the phenotypic effects of another gene (eg. Baldness is epistatic
to blondness)
, Complementation - Correct Answers -Mutations are in two different genes.
-Two parents with "mutant" produce normal progeny.
-Happens because parents have defects in two DIFFERENT genes.
No complementation - Correct Answers -Mutations in the same gene.
Complementation analysis - Correct Answers -Allows us to determine whether two such
mutations are in the same gene.
Recessive epistasis - Correct Answers -Two or more genes can both be involved in
producing a particular phenotype.
Extranuclear inheritance - Correct Answers -Transmission of traits by genetic
information contained in cytoplasmic organelles such as mitochondria and cytoplasts.
Cytoplasmic inheritance - Correct Answers -Ex. mitochondrial inheritance:
Mitochondria have their own DNA.
•small circle of DNA with 37 genes.
-These genes function in energy production and protein assembly.
•Mitochondria are only passed along from the MOTHER.
Mitochondrial inheritance - Correct Answers --Passed from affected mothers to all
offspring•Affected fathers do not pass on the trait.
-Severity frequently related to the proportion of mutant mitochondria inherited at birth.
Maternal effect - Correct Answers -Genes are inherited from both parents, but the
phenotype of the offspringis determined by the genotype of the mother.
Loss of function mutation - Correct Answers --m/+ has normal phenotype
-reduces or eliminates the function of a gene product
Gain of function mutation - Correct Answers --m/+ has a mutant phenotype
-almost always dominant
-gene product has an enhanced, negative or new function
-change in regulation so gene is expressed at new time or in new location
A change in one base-pair to another in a DNA molecule is known as - Correct Answers
-A point mutation or a base substitution
Point mutation - Correct Answers -A mutation that can be mapped to a single locus.
Base substitution - Correct Answers -A single base change that produces a mutation.
