exam 2

Question 1

If the allele frequency of the dominant allele is 0.4, what value is used for the term p2 in the equation p2 + 2pq + q2 = 1?

Answer 1

0.16

Question 2

Genetic drift has the greatest influence on allele frequencies for which population size?

Answer 2

small

Question 2

A SNP would best be described as

Answer 2

a single nucleotide difference between two DNA sequences.

Question 3

Migration of a random few individuals from one population to a new area to establish a new population is an example of

Answer 3

founder effect.

Question 4

Given the allele frequency for a gene in population A is 0.3 and the frequency for the same allele in population B is 0.5 and that 25 individuals from A migrate to and mate randomly with the 475 individuals in population B, what is the new allele frequency (PC) in the conglomerate?

Answer 4

0.49

Question 5

Which type of selection would lead to two distinct phenotypes?

Answer 5

disruptive selection

Question 5

The term for the mating for two genetically unrelated individuals is

Answer 5

outbreeding.

Question 6

The prevalence of the allele for sickle cell anemia in some populations is an example of which of the following?

Answer 6

balancing selection

Question 7

By what process do new alleles arise?

Answer 7

Mutation

Question 8

Repetitive sequences are useful for DNA fingerprinting because they

Answer 8

are inherited and can show significant variability between individuals.

Question 9

Calculate the narrow-sense heritability of height between aunts and nieces if the observed phenotypic correlation coefficient is 0.1.

Answer 9

0.4

Question 10

A heritability value of 0.997 indicates which of the following?

Answer 10

The majority of the phenotypic variation has a genetic basis.

Question 11

Which of the following steps is NOT used in conducting a backcross in order to map a QTL?

Answer 11

The F1 offspring are crossed with each other.

Question 12

For a quantitative trait, the total variance of the population is due to which of the following?

Answer 12

The sum of the genetic and environmental variances

Question 13

Which of the following is incorrect concerning quantitative traits?

Answer 13

Individuals fall into distinct classes for comparison.

Question 14

After several generations of artificial selective breeding, a plateau is reached where artificial selection is no longer effective. This is called the _______.

Answer 14

selection limit

Question 15

In calculations of the degrees of freedom for a correlation coefficient, what value does the degrees of freedom take?

Answer 15

(n - 2)

Question 15

After calculating a correlation coefficient, you discover that the value is not significant at the 5% level. What can be done that may result in a significant difference?

Answer 15

increase the sample size

Question 16

When analyzing two variables, the strength of the association between the variables is called the ____.

Answer 16

correlation coefficient

Question 17

Which of the following best describes the degrees of freedom for the calculation of variance?

Answer 17

(n - 1)

Question 18

Crossing over is more likely to occur between genes that are ______ on a chromosome.

Answer 18

far apart

Question 19

In a mapping cross, you determine that the recombination frequency between the Q and P is 12% and between loci Q and L is 15%. If locus Q is in between loci P and L, then the recombination frequency between P and L should be approximately __________.

Answer 19

27%

Question 20

A testcross is always performed between the individual that is heterozygous for the genes to be mapped and an individual who is _____.

Answer 20

homozygous recessive for the genes

Question 21

Twin spotting provides evidence of what genetic event?

Answer 21

mitotic recombination

Question 22

The diploid garden pea plant has 14 chromosomes. The haploid fungus Neurospora crassa has 7 chromosomes. Neither organism has separate male and female individuals. Which of the following correctly identifies the number of linkage groups in each organism?

Answer 22

Garden pea has 7 linkage groups, and Neurospora has 7.

Question 23

Which of the following defines gene linkage?

Answer 23

Both two or more genes that are physically connected on a chromosome and genes that are transmitted to the next generation as a group.

Question 24

Another name for a chromosome is a _______, since it contains genes that are often inherited together.

Answer 24

linkage group

Question 25

Experimental evidence that crossing over occurs between the X chromosomes of female Drosophila was provided by _____.

Answer 25

Morgan

Question 26

Creighton and McClintock worked with _____ as their model system to show that homologous chromosomes physically exchange genetic information during crossing over.

Answer 26

corn

Question 27

Suppose the genes for eye color and wing shape are both on the X chromosome (they are linked) and are known to be 68 map units apart. In a mating between a Xw+m+Xwm female and a XwmY male that produces 1000 progeny, how many recombinant progeny would you expect to observe?

Answer 27

500

Question 28

The common goldfish Carassius auratus has 100 chromosomes and is tetraploid. The goldfish therefore has __________ sets of chromosomes containing __________ chromosomes each.

Answer 28

4; 25

Question 29

A _______ translocation occurs when a piece of one chromosome is attached to another chromosome.

Answer 29

simple

Question 30

The salivary amylase gene (AMY1) is present in two diploid copies in chimpanzees. Humans are known to have between 6-15 copies, an adaptation that is thought to be related to the high-starch diet of humans. This difference among humans is an example of __________.

Answer 30

copy number variation

Question 31

Inversion loops can occur in which of the following?

Answer 31

both paracentric inversions and pericentric inversions

Question 32

The African clawed frog (Xenopus laevis) is an allotetraploid, likely as a result of an interspecies mating long ago, followed by a duplication of the entire genome. Xenopus laevis is fertile and has a normal life cycle. In contrast, mules, the allodiploid offspring of a male donkey and a female horse, are generally sterile. Why can Xenopus reproduce and mules cannot?

Answer 32

In allotetraploid organisms each chromosome has a chromosome to pair up with in meiosis, whereas in allodiploid organisms they do not.

Question 33

Genetic abnormalities that occur after fertilization may result in some tissues of the body differing in their genetic composition. This is called ________.

Answer 33

mosaicism

Question 34

Which correctly describes mitotic nondisjunction?

Answer 34

It is a relatively rare event. It results in the loss of chromosomes in some cells. It usually does not affect all of the cells of the organism.

Question 35

The short arm of a chromosome is denoted by the letter _______ and the long arm by the letter _______.

Answer 35

p; q

Question 36

What are Klinefelter and Turner syndromes examples of?

Answer 36

sex chromosome aneuploidy

Question 37

The polytene chromosomes of Drosophila are an example of _________.

Answer 37

polyploidy