Deck 7: Multifactorial Traits

Question 1

Empiric risk is based on _____,which is the _____.

A)prevalence;rate at which a certain event occurs
B)incidence;rate at which a certain event occurs
C)prevalence;proportion of individuals in a population with a particular disorder at a specific time
D)incidence;proportion of individuals in a population with a particular disorder at a specific time

Answer 1

B

Question 2

Polygenic traits are

A)determined by a single gene.
B)determined by more than one gene.
C)phenotypically different in different organisms.
D)associated with many symptoms.

Answer 2

B

Question 3

Skin color is not a good way to distinguish "races" of people because

A)it can be changed by environmental factors.
B)it is but one of many traits that vary within and between human populations.
C)it is not inherited.
D)it changes over a person's lifetime.

Answer 3

B

Question 4

Multifactorial traits include

A)only polygenic traits.
B)neither single gene nor polygenic traits.
C)both single gene and polygenic traits.
D)only traits that have no genetic cause.

Question 5

Fingerprint pattern is inherited,but also affected by the environment.An example of how the environment naturally can alter fingerprint pattern is

A)a criminal taking off the fingertip skin with acid.
B)a fetus touching the developing toe and finger pads to the wall of the amniotic sac.
C)a person developing skin disorders.
D)the fingertips rubbing away from too much computer use.

Question 6

DNA sequences that contribute to polygenic traits are called

A)qualitative trait loci.
B)quantitative trait loci.
C)multifactorial trait loci.
D)single nucleotide polymorphisms.

Question 7

Average height of college students increased throughout the 20th century because

A)more students attended college.
B)more short students went into military service instead of college.
C)nutrition improved greatly in that time.
D)many mutations conferring great height occurred during that time perioD.

Question 8

"Total ridge count" is

A)a multifactorial trait that considers the number of ridges in whorls,loops,or arches of the finger pad skin.
B)a single gene trait that counts the number of ridges in the small intestine.
C)the number of wives of Ridge Forrester,a character on "The Bold and the Beautiful."
D)a polygenic trait that considers the number of lines of pigment in the irises.

Question 9

The pattern of genetic transmission typical of a multifactorial trait is

A)discontinuous distributions such as 3:1.
B)that of Mendelian inheritance.
C)continuous variation of phenotypic expression.
D)a 9:3:3:1 ratio.

Question 10

Traditional ways of evaluating multifactorial traits include

A)empiric risk and heritability.
B)Punnett squares and pedigrees.
C)surveys that ask people what they have been exposed to.
D)tests for several Mendelian traits or diseases.

Question 11

The distinction between multifactorial and polygenic traits is that

A)polygenic traits are caused by more than one gene,and multifactorial traits are caused by one or more genes as well as environmental influences.
B)multifactorial traits are not genetic,and polygenic traits are genetic.
C)the genetic component can be determined for polygenic traits but not for multifactorial traits.
D)polygenic traits are caused by more than one gene,and multifactorial traits are caused by only one gene.

Question 12

The difference between cystic fibrosis and migraine is that the

A)former is caused by various environmental factors.
B)former can be traced to a single gene.
C)former is caused by the absence of a chromosome.
D)latter is a Mendelian trait.

Question 13

Traits that have both inherited and environmental causes are termed

A)heritable.
B)polygenic.
C)multifactorial.
D)familial.

Question 14

People with very light skin have _____.

A)more melanocytes than people with very dark skin.
B)fewer melanocytes than people with very dark skin.
C)about the same number of melanocytes as people with very dark skin.
D)red melanocytes.

Question 15

Mendel's laws

A)do not apply to multifactorial traits.
B)apply to multifactorial traits but may be difficult to follow because different genes contribute in different degrees to a phenotype.
C)operate in some genes that contribute to a multifactorial trait,but not in others.
D)apply only to polygenic,but not multifactorial traits.

Question 16

For a multifactorial,polygenic trait,the characteristic shape of the mathematical plot of frequency for each phenotype class is

A)linear,going up.
B)linear,going down.
C)a bell curve.
D)a square curve.

Question 17

The number of genes that affect skin,hair,and eye color is

A)less than 4.
B)less than 8.
C)more than 20,000.
D)more than 100.

Question 18

Rasheed suffers terrible migraine headaches.They are likely caused by

A)at least three genes and perhaps environmental triggers,such as foods.
B)a single gene but no environmental influences.
C)a missing chromosome.
D)poor diet and susceptibility to infection.

Question 19

A continuously varying trait is

A)cystic fibrosis.
B)seed color in pea plants.
C)extra fingers and toes.
D)weight in humans.

Question 20

In a polygenic trait

A)within genes,all alleles affect the phenotype to the same degree.
B)all alleles are dominant.
C)genes contribute to varying degrees,and alleles have differing degrees of impact.
D)one gene can cancel out the effect of the environment.

Question 21

The empiric risk that the monozygotic twin of a person with cleft lip also has cleft lift is _____ times the risk to a member of the general population who has no relatives with cleft lip.

A)4
B)40
C)100
D)400

Question 22

Heritability refers to

A)the genetic contribution to a phenotype in a population at a particular time.
B)the genetic contribution to the variability of a phenotype in a population at a particular time.
C)the number of genes contributing to a trait in a population.
D)the degree to which offspring resemble parents.

Question 23

A major distinction of genome-wide association (GWA)studies,compared to the more traditional approaches of empiric risk,heritability,adoptee and twin studies,is that

A)GWA studies pepper the entire genome with markers,so that even genes that would not be expected to contribute to a phenotype can be discovered.
B)GWA studies actually sequence entire genomes.
C)GWA studies can be performed on healthy individuals.
D)GWA studies consider already-known traits.

Question 24

An assumption of twin studies is that

A)twins are more intelligent than singletons.
B)both twins of a pair have had similar experiences.
C)the twins are monozygotiC.
D)the twins are dizygotic.

Question 25

A brother and sister share _____ percent of their genes.

A)10
B)25
C)50
D)100

Question 26

Heritability of a trait can change because

A)genes mutate.
B)the environment can change.
C)a person can consciously change her or his heritability.
D)the heritability in a family changes with the number of children.

Question 27

If a trait has a large inherited component,then concordance among monozygotic twins will be

A)considerably higher than that of dizygotic twins.
B)considerably lower than that of dizygotic twins.
C)about the same as that of dizygotic twins.
D)100%.

Question 28

Studies that implicate the environment in influencing body weight consider

A)indigenous populations where the people have lived in the same area for thousands of years and tend to all be thin.
B)populations that split,with some people remaining in the homeland and others moving to areas where their diet changes dramatically,and they gain a great deal of weight.
C)mice bred to be obese that are given different types of junk food.
D)SNPs located throughout the genome.

Question 29

The proportion of shared genes between a grandparent and grandchild is _____ percent.

A)10
B)25
C)50
D)100

Question 30

In humans,heritability of clubfoot is 0.8.This means that expression of this condition is

A)strongly influenced by environmental factors.
B)solely dependent on inheritance of the clubfoot gene(s).
C)strongly dependent on inheritance of the clubfoot gene(s)but also influenced by environmental factors.
D)inherited from an affected parent 80% of the time.

Question 31

A cohort study looks at

A)a large group of people over time,keeping track of specific health conditions or measures.
B)large groups of DZ and MZ twins.
C)heritabilities of behavioral characteristics.
D)patterns of copy number variants in the human genome.

Question 32

Concordance refers to

A)percentage of monozygotic twin pairs in which neither express the trait.
B)percentage of monozygotic twin pairs in which both express the trait.
C)percentage of dizygotic twin pairs in which both express the trait.
D)percentage of twin pairs in which both express a trait among pairs in which at least one twin has the trait.

Question 33

Geneticists designate heritability as "narrow" or "broad" to account for the fact that

A)genes contribute to different degrees.Typically,recessive alleles are rare and can have a large impact and dominant alleles tend to be common with minor but additive effects.
B)genes contribute to different degrees.Typically,dominant alleles are rare and have a small impact and recessive alleles tend to be common,each with major effects.
C)genes contribute to different degrees.Typically,dominant alleles are rare and can have a large impact and recessive alleles tend to be common with minor but additive effects.
D)dominant and recessive alleles have equal impact,but dominant alleles are more common than recessive alleles.

Question 34

The DNA of dizygotic twins is

A)identical in the number and distribution of copy number variants,but not necessarily in sequence.
B)different in the number and distribution of copy number variants,but not necessarily in sequence.
C)identical in the number and distribution of copy number variants and in sequence.
D)as alike as the DNA of any two full siblings.

Question 35

Genes that help to control body weight encode the proteins

A)fibrin,fibrinogen,and hemoglobin.
B)collagen,elastin,and dystrophin.
C)estrogen,testosterone,and progesterone.
D)leptin,ghrelin,and the melanocortin-4 receptor.

Question 36

To date,the most informative studies on how and to what degree heredity and the environment influence human traits have relied on data from

A)adopted children and their biological parents.
B)monozygotic twins reared in the same environment.
C)monozygotic twins separated at birth.
D)Egyptian mummies.

Question 37

The coefficient of relatedness indicates

A)the number of relatives with a certain trait.
B)the proportion of genes that types of relatives share.
C)the heritability of a trait.
D)the number of genes responsible for a polygenic trait.

Question 38

The empiric risk to a family member of an affected individual developing a disorder caused by a multifactorial trait

A)decreases with severity of the disorder.
B)increases with fewer affected family members.
C)decreases in larger families.
D)increases with increasing relatedness to affected individuals.

Question 39

A gene discovery technique that looks at regions of the genome where individuals have the same alleles much more often than expected by chance,because their ancestors were blood relatives,is called

A)homozygosity mapping.
B)heterozygosity mapping.
C)the defective sibling pair approach.
D)empiric risk.

Question 40

Two brothers share _____ percent of their genes.

A)10
B)25
C)50
D)100