Genetics and Inheritance Patterns in Human Diseases and
Traits – Questions and Answers
Terms in this set (500)
Genetic inheritance The mechanisms by which an individual's set of paired chromosomes produce traits.
Mendelian traits Traits caused by single genes, named after Gregor Mendel.
Locus A position along a chromosome where a gene is located.
Alleles Different forms of a gene that can occupy a locus.
A locus that has two or more alleles occurring with appreciable frequency in a
Polymorphic
population.
Diploid organisms Organisms that have two sets of chromosomes, one from each parent.
Homozygous An individual with identical alleles at a given locus.
Heterozygous An individual with non-identical alleles at a given locus.
Genotype The composition of genes at a given locus.
Phenotype The outward appearance based upon genotype and environment.
A single-gene disorder characterized by an inability to metabolize the amino acid
Phenylketonuria (PKU)
phenylalanine.
An allele whose effects are observable and masks those of another allele in a
Dominant allele
heterozygote.
An allele whose effects are hidden and must exist in homozygous form to be
Recessive allele
expressed.
Carrier An individual who has a disease gene but is phenotypically normal.
Mode of inheritance The pattern in which a genetic disease is inherited through generations.
A potential outcome of untreated phenylketonuria due to the accumulation of
Intellectual disability
abnormal metabolites.
Exclusion of foods high in phenylalanine, such as milk, dairy products, meat, fish,
Dietary restrictions for PKU
chicken, eggs, beans, and nuts.
, The condition where recessive alleles are expressed, often leading to lethal
Homozygous recessive
outcomes.
Providing reliable information about the disease-causing gene based on the mode
Genetic counseling
of inheritance.
Substances that accumulate in the brain of infants with untreated phenylketonuria,
Abnormal metabolites
leading to intellectual disability.
Changes in the environment, such as diet, that can alter the phenotype without
Environmental modification
changing the genotype.
Uppercase letter in genetics Denotes a dominant allele.
Lowercase letter in genetics Denotes a recessive allele.
A mode of inheritance where affected offspring are produced by the union of a
Autosomal dominant
normal parent with an affected heterozygous parent.
A mode of inheritance that involves genes known to occur on the 22 pairs of
Autosomal recessive
autosomes.
A mode of inheritance where the disease-causing genes occur on the X
X-linked dominant
chromosome.
A mode of inheritance where the disease-causing genes occur on the X
X-linked recessive
chromosome.
Proband The first person in a family diagnosed or seen in a clinic for a genetic disease.
Diseases caused by autosomal dominant genes are rare, occurring in fewer than 1 in
Transmission of autosomal dominant genes
500 individuals.
A diagram used to predict the outcome of a
genetic cross, illustrating the mating of individuals
Punnett Square
with specific traits.
Recurrence risk The probability that an individual will develop a genetic disease.
A new genetic alteration that can occur in a child born with an autosomal dominant
Mutation
disease when there is no history of the disease in the family.
The principle that each birth is an independent event regarding the recurrence risk
Independent event
of a genetic disease.
Individuals who carry one disease-causing allele and can transmit the trait to
Affected heterozygous individuals
approximately half their children.
In autosomal dominant inheritance, both males and females exhibit the trait in
Equal proportions in sexes
approximately equal proportions.
In autosomal dominant inheritance, if an individual has the trait, one parent must also
No generations skipped
have it.
If neither parent has the trait in autosomal dominant inheritance, none of the children
Transmission of traits
will have it.
The principle stating that the probability of the next child having a genetic disease
Law of independence
remains the same regardless of previous births.
Offspring produced by the union of a normal parent with an affected heterozygous
Affected offspring
parent in autosomal dominant inheritance.
Traits – Questions and Answers
Terms in this set (500)
Genetic inheritance The mechanisms by which an individual's set of paired chromosomes produce traits.
Mendelian traits Traits caused by single genes, named after Gregor Mendel.
Locus A position along a chromosome where a gene is located.
Alleles Different forms of a gene that can occupy a locus.
A locus that has two or more alleles occurring with appreciable frequency in a
Polymorphic
population.
Diploid organisms Organisms that have two sets of chromosomes, one from each parent.
Homozygous An individual with identical alleles at a given locus.
Heterozygous An individual with non-identical alleles at a given locus.
Genotype The composition of genes at a given locus.
Phenotype The outward appearance based upon genotype and environment.
A single-gene disorder characterized by an inability to metabolize the amino acid
Phenylketonuria (PKU)
phenylalanine.
An allele whose effects are observable and masks those of another allele in a
Dominant allele
heterozygote.
An allele whose effects are hidden and must exist in homozygous form to be
Recessive allele
expressed.
Carrier An individual who has a disease gene but is phenotypically normal.
Mode of inheritance The pattern in which a genetic disease is inherited through generations.
A potential outcome of untreated phenylketonuria due to the accumulation of
Intellectual disability
abnormal metabolites.
Exclusion of foods high in phenylalanine, such as milk, dairy products, meat, fish,
Dietary restrictions for PKU
chicken, eggs, beans, and nuts.
, The condition where recessive alleles are expressed, often leading to lethal
Homozygous recessive
outcomes.
Providing reliable information about the disease-causing gene based on the mode
Genetic counseling
of inheritance.
Substances that accumulate in the brain of infants with untreated phenylketonuria,
Abnormal metabolites
leading to intellectual disability.
Changes in the environment, such as diet, that can alter the phenotype without
Environmental modification
changing the genotype.
Uppercase letter in genetics Denotes a dominant allele.
Lowercase letter in genetics Denotes a recessive allele.
A mode of inheritance where affected offspring are produced by the union of a
Autosomal dominant
normal parent with an affected heterozygous parent.
A mode of inheritance that involves genes known to occur on the 22 pairs of
Autosomal recessive
autosomes.
A mode of inheritance where the disease-causing genes occur on the X
X-linked dominant
chromosome.
A mode of inheritance where the disease-causing genes occur on the X
X-linked recessive
chromosome.
Proband The first person in a family diagnosed or seen in a clinic for a genetic disease.
Diseases caused by autosomal dominant genes are rare, occurring in fewer than 1 in
Transmission of autosomal dominant genes
500 individuals.
A diagram used to predict the outcome of a
genetic cross, illustrating the mating of individuals
Punnett Square
with specific traits.
Recurrence risk The probability that an individual will develop a genetic disease.
A new genetic alteration that can occur in a child born with an autosomal dominant
Mutation
disease when there is no history of the disease in the family.
The principle that each birth is an independent event regarding the recurrence risk
Independent event
of a genetic disease.
Individuals who carry one disease-causing allele and can transmit the trait to
Affected heterozygous individuals
approximately half their children.
In autosomal dominant inheritance, both males and females exhibit the trait in
Equal proportions in sexes
approximately equal proportions.
In autosomal dominant inheritance, if an individual has the trait, one parent must also
No generations skipped
have it.
If neither parent has the trait in autosomal dominant inheritance, none of the children
Transmission of traits
will have it.
The principle stating that the probability of the next child having a genetic disease
Law of independence
remains the same regardless of previous births.
Offspring produced by the union of a normal parent with an affected heterozygous
Affected offspring
parent in autosomal dominant inheritance.
