GENETICS CH

True or false: Comparing someone with a genetic disease to another person in the general population, the person with the disease is more likely to have a family member with the same disease.

True

What is the inheritance pattern for a trait that more commonly affects males than females and can often be observed in brothers or fathers of a woman who has affected sons?

X-linked recessive

Characteristics that are determined by several genes and are also influenced by environmental factors are called _____ traits.

complex

Quantitative traits are ______.

controlled by multiple genes

The goal of a ______ study is to find a relationship between one or more single-nucleotide polymorphisms (SNPs) and a disease or other human trait.

genome-wide association

Quantitative traits tend to show a continuum of variation because they are usually______ , meaning that they are controlled by multiple genes.

polygenic

Heritability is a measurement of the ______.

proportion of phenotypic variance due to genetic variance

A complex trait is a trait that is influenced by ______.

several genes and the environment

When a human disease is caused by a mutation in a single gene, the pattern of inheritance is called _______ Mendelian inheritance.

simple

When a defect in a single gene causes a human disease, the mutant gene often follows ______.

simple Mendelian inheritance patterns

Which of the following are examples of quantitative traits?

- Number of bristles in Drosophila - Speed of flight in birds - Blood pressure in humans

In a normal distribution, what percentage of all individuals have phenotypic values within one standard deviation of the mean?

68%

If a population fits a normal distribution, then what percentage of individuals have phenotypic values within two standard deviations above or below the mean?

95%

Which best describes a haplotype?

A haploid genotype showing linkage of alleles or molecular markers along a single chromosome

Which field of genetics involves the statistical study of biological traits?

Biometrics

The graphs show the relationship between seed weight and genotype for a single gene that influences seed weight. Which statement describes the difference between the two graphs?

Graph A shows a low environmental effect on seed weight, whereas Graph B shows a high environmental effect

What is a quantitative trait locus?

The chromosomal location of one or more genes that affect the phenotype of a quantitative trait

What is the focus of the biometric field of genetics?

The statistical study of biological traits

Approximately how many human diseases have a genetic basis?

Thousands

When phenotypic variance is determined solely by genotypic and environmental variance, and genetic and environmental factors are independent of one another, then total phenotypic variance is equal to genetic variance _____ environmental variance.

and

An examination of the genomes of many different individuals to determine if a specific genetic variant is associated with a human disease is called a genome-wide ____ ____.

association study

A graph that presents phenotypic categories on the x-axis and the number of individuals that fall into a category on the y-axis is called a(n) _____ distribution.

frequency

The linkage of alleles or molecular markers along a single chromosome is called a ______.

haplotype

An association between a disease-causing allele and nearby molecular markers can be established because ______.

haplotypes do not usually change from generation to generation

For a particular population in a particular environment, the fraction of phenotypic variance that is due to genetic variance is called

heritable

The chromosomal location of one or more genes that influence a quantitative trait is called a quantitative trait ______ .

loci

The graph shows a hypothetical situation in which seed weight is controlled by three genes, each with light (w) and heavy (W) alleles, and a low environmental effect. If the environmental effect were high, ______.

the overlaps between genotypes increases

In bread wheat, the color of the hull can be dark red, white, or various intermediate shades of red. Genetic analysis of this trait has demonstrated that it is controlled by ______. Multiple choice question.

two loci with additive effects on hull color

The standard deviation of a data set is equal to the square root of the ______.

variance

What is the inheritance pattern for a trait that occurs with equal frequency in both sexes and will be inherited, on average, by 50% of the offspring of an affected individual who had only one affected parent?

Autosomal dominant

True or false: Genetic diseases often show a specific age of onset.

True

How many genes control hull color in bread wheat?

Two

Which of the following formulas is the correct equation for calculation of the mean? In these equations, X is the mean, ΣX is the sum of all values in the group, and N is the number of individuals in the group.

X= ΣX/N

A situation where a disease may be caused by mutations in two or more different genes is called ______.

locus heterogeneity

The disease hemophilia is caused by a deficiency in any one of three blood clotting factors. Two of these factors are encoded by genes on the X chromosome and the other clotting factor gene is located on an autosome. Since mutations in more than one gene can cause hemophilia, this represents ______.

locus heterogeneity

When a new mutation establishes a disease-causing allele in a family member, the allele's location can be traced through ______.

markers in a haplotype that are located nearby

The accompanying pedigree shows the inheritance of Huntington disease with filled symbols and also indicates which combination of four possible forms (A, B C, D) of a molecular marker called G8 that the person has inherited. Although there are some exceptions, the inheritance of Huntington disease is most closely associated with which form of the G8 marker in this pedigree?

C

What is the inheritance pattern for a trait that more commonly affects males than females and which will occur in about 50% of the sons born to the unaffected daughter of an affected male?

X-linked recessive

The sum of all of the values of a parameter within a group divided by the number of individuals in the group is defined as the ______.

mean

What is the inheritance pattern when a trait occurs with the same frequency in both sexes and an affected offspring can have two unaffected parents?

Autosomal recessive

What is the inheritance pattern when the trait occurs with the same frequency in both sexes and two unaffected heterozygotes have, on average, 25% affected children?

Autosomal recessive

The accompanying pedigree shows the inheritance of Huntington disease with filled symbols and also indicates which combination of four possible forms (A, B C, D) of a molecular marker called G8 that the person has inherited. What is the one possible phenotype and marker combination that is missing among the children of the couple surrounded by the circle?

BB with Huntington disease

Simple Mendelian inheritance is a pattern observed when a human disorder is caused by ______.

mutation in a single gene

What is the inheritance pattern for a trait that occurs with the same frequency in both sexes and two affected heterozygous individuals have, on average, 25% unaffected offspring?

Autosomal dominant

A frequency distribution is a graph that shows the ______.Wh

number of individuals in various phenotypic categories

The length of an ear of corn is an example of a(n) _____ trait.

quantitative