Deck 21: Genetics of Complex Traits

Question 1

Multifactorial inheritance is observed in phenotypes that show typically

A)only one discrete type.
B)two extremes.
C)a bell-shaped distribution.
D)a higher mutation rate.
E)All of the choices are correct.

Answer 1

a bell-shaped distribution.

Question 2

Broad sense heritability is defined as

A)V_G.
B)V_P.
C)V_E.
D)V_G/V_P.
E)V_P/V_G.

Answer 2

V_G/V_P.

Question 3

Which of the following is not true about monozygotic twins?

A)They share all alleles at all loci.
B)They have a genetic relatedness of 0.5.
C)They have a genetic relatedness of 1.0.
D)They come from the joining of a single egg with a single sperm cell.
E)They are the result of a split of the zygote after fertilization.

Answer 3

They have a genetic relatedness of 0.5.

Question 4

The total genetic relatedness of two siblings is

A)2.0
B)1.0
C)0.5
D)0.2
E)None of the choices is correct.

Question 5

Introgressions are used to

A)fine map QTLs
B)establish linkage disequilibrium.
C)establish linkage equilibrium.
D)rough map QTLs.

Question 6

Multifactorial traits

A)are affected by both genetic and environmental factors.
B)usually do not result in continuous phenotypes.
C)are not usually affected by environmental conditions.
D)usually result in one or two phenotypic values such as red/white eye color in Drosophila.

Question 7

The response to selection, R, is equal to

A)the heritability (h²) of a trait.
B)the strength (S) of selection.
C)the difference between h² and S.
D)S/h².
E)h²S.

Question 8

The total phenotype variance (V_P) is

A)the sum of genetic variance (V_G) and environmental variance (V_E).
B)the difference between V_G and V_E.
C)not dependent on V_G.
D)not dependent on V_E.
E)always constant.

Question 9

Twins from two individual zygotes (dizygotic twins)

A)are related genetically the same as monozygotic twins.
B)share 0% genetic similarities.
C)are similar in 100% of genetic sequences.
D)are related genetically the same as non-twin siblings.
E)are similar to the parents.

Question 10

By definition linkage disequilibrium means that

A)two alleleic variants correlate with the presence of a particular phenotype.
B)two alleleic variants do not correlate with the presence of a particular phenotype.
C)that two alleleic variants are at least 60 mu apart.
D)two alleleic variants are 50 mu apart

Question 11

In an experiment to distinguish genetic versus environmental effects on a phenotype it is important to make sure that the test individuals

A)are as genetically identical as possible
B)have the greatest varinace at all losi as possilble
C)have the same parents
D)are subjected to a natural environment.

Question 12

A number of interacting genes produce quantitative inheritance.The transmission of these genes can be seen in the phenotypical pattern of

A)discontinuous distribution of discrete phenotypes.
B)continuous variation in phenotypic expression.
C)strict dominance and recessiveness.
D)All of the choices are correct.
E)only discontinuous distribution of discrete phenotypes and continuous variation in phenotypic expression.