BIO 110 EXAM 3 QUESTIONS WITH
CORRECT ANSWERS
carrier - Correct Answers -person (or other organism) who is heterozygous for a
recessive trait and does not display the trait or show symptoms of the condition
codominance - Correct Answers -a relationship between the alleles of a gene wherein
the alleles in a heterozygote are both fully expressed. This results in offspring with a
phenotype that is neither dominant nor recessive and is a unique phenotype
complete dominance - Correct Answers -a relationship between alleles of a gene
wherein the allele that is dominant completely masks the effect of the allele that is
recessive in the heterozygote
epistasis - Correct Answers -the phenomenon where the effect of one gene is
dependent on the presence of one or more other genes. In other words, one gene
influences the expression of another gene.
heterozygote advantage - Correct Answers -a phenomenon wherein the heterozygous
genotype has a higher relative fitness than either the homozygous dominant or
homozygous recessive genotype.
incomplete dominance - Correct Answers -relationship between alleles in which one
allele for a specific trait is not completely expressed over its paired allele. This results in
a third phenotype in which the expressed physical trait is a combination of the
phenotypes of both alleles.
genetic recombination - Correct Answers -the production of gametes and offspring with
combinations of alleles that differ from those found in either parent
linkage map - Correct Answers -a chromosome map that shows the position of genes
relative to each other in terms of recombination frequency, rather than a specific
physical distance along each chromosome
linked genes - Correct Answers -genes that are closer than 50 map units apart on a
chromosome
multiple alleles - Correct Answers -the condition wherein a gene has three or more
possible alleles
pedigree - Correct Answers -a diagram that shows the occurrence of phenotypes of a
particular gene from one generation to the next
, pleiotropy - Correct Answers -a phenomenon where one gene influences two or more
seemingly unrelated phenotypic traits
polygenic inheritance - Correct Answers -occurs when one characteristic is controlled by
two or more genes
quantitative character - Correct Answers -a phenotype that depends on the combined
actions of many genes and the environment
autosome - Correct Answers -a non-sex chromosome
barr body - Correct Answers -the inactive X chromosome typically in a female somatic
cell. Barr bodies occur in any mammalian cell in which there are 2 or more X
chromosomes
hemizygous - Correct Answers -the condition of having only a single copy of a gene or
chromosome instead of the typical two copies. Males are hemizygous for genes on the
X and Y chromosome
mutant phenotype - Correct Answers -a phenotype that is less common in a population
than the wild-type phenotype. For example, in fruit flies white eyes are a mutant
phenotype
sex-linked genes - Correct Answers -genes that are carried on either sex chromosome
SRY gene - Correct Answers -the gene that is responsible for the initiation of male sex
determination in humans. The SRY gene codes for a transcription factor that turns on
other genes related to male development
wild-type phenotype - Correct Answers -the most common phenotype for a character in
a population. for example, in fruit flies red eyes are the wild-type phenotype
XIST gene - Correct Answers -the gene on the X chromosome of mammals that results
on the formation of a Barr body. The XIST gene inactivates the X chromosome
complete linkage - Correct Answers -the situation in which two genes are so close
together that alleles of these genes are not separated by crossing over
genetic map - Correct Answers -a map that shows the location of genes on a
chromosome
map unit - Correct Answers -a unit for measuring genetic linkage. defined as the
distance between genes for which the expected cross-over frequency is 1%
CORRECT ANSWERS
carrier - Correct Answers -person (or other organism) who is heterozygous for a
recessive trait and does not display the trait or show symptoms of the condition
codominance - Correct Answers -a relationship between the alleles of a gene wherein
the alleles in a heterozygote are both fully expressed. This results in offspring with a
phenotype that is neither dominant nor recessive and is a unique phenotype
complete dominance - Correct Answers -a relationship between alleles of a gene
wherein the allele that is dominant completely masks the effect of the allele that is
recessive in the heterozygote
epistasis - Correct Answers -the phenomenon where the effect of one gene is
dependent on the presence of one or more other genes. In other words, one gene
influences the expression of another gene.
heterozygote advantage - Correct Answers -a phenomenon wherein the heterozygous
genotype has a higher relative fitness than either the homozygous dominant or
homozygous recessive genotype.
incomplete dominance - Correct Answers -relationship between alleles in which one
allele for a specific trait is not completely expressed over its paired allele. This results in
a third phenotype in which the expressed physical trait is a combination of the
phenotypes of both alleles.
genetic recombination - Correct Answers -the production of gametes and offspring with
combinations of alleles that differ from those found in either parent
linkage map - Correct Answers -a chromosome map that shows the position of genes
relative to each other in terms of recombination frequency, rather than a specific
physical distance along each chromosome
linked genes - Correct Answers -genes that are closer than 50 map units apart on a
chromosome
multiple alleles - Correct Answers -the condition wherein a gene has three or more
possible alleles
pedigree - Correct Answers -a diagram that shows the occurrence of phenotypes of a
particular gene from one generation to the next
, pleiotropy - Correct Answers -a phenomenon where one gene influences two or more
seemingly unrelated phenotypic traits
polygenic inheritance - Correct Answers -occurs when one characteristic is controlled by
two or more genes
quantitative character - Correct Answers -a phenotype that depends on the combined
actions of many genes and the environment
autosome - Correct Answers -a non-sex chromosome
barr body - Correct Answers -the inactive X chromosome typically in a female somatic
cell. Barr bodies occur in any mammalian cell in which there are 2 or more X
chromosomes
hemizygous - Correct Answers -the condition of having only a single copy of a gene or
chromosome instead of the typical two copies. Males are hemizygous for genes on the
X and Y chromosome
mutant phenotype - Correct Answers -a phenotype that is less common in a population
than the wild-type phenotype. For example, in fruit flies white eyes are a mutant
phenotype
sex-linked genes - Correct Answers -genes that are carried on either sex chromosome
SRY gene - Correct Answers -the gene that is responsible for the initiation of male sex
determination in humans. The SRY gene codes for a transcription factor that turns on
other genes related to male development
wild-type phenotype - Correct Answers -the most common phenotype for a character in
a population. for example, in fruit flies red eyes are the wild-type phenotype
XIST gene - Correct Answers -the gene on the X chromosome of mammals that results
on the formation of a Barr body. The XIST gene inactivates the X chromosome
complete linkage - Correct Answers -the situation in which two genes are so close
together that alleles of these genes are not separated by crossing over
genetic map - Correct Answers -a map that shows the location of genes on a
chromosome
map unit - Correct Answers -a unit for measuring genetic linkage. defined as the
distance between genes for which the expected cross-over frequency is 1%
