OAT Genetics and Evolution

Question 1

Which of the following best describes the law of independent assortment?

Accepted Answer

Genes on different chromosomes are inherited independently of one another

Answer

Alleles of a gene segregate equally into gametes

Answer

Dominant alleles always mask recessive alleles

Answer

Linked genes are always inherited together

Question 2

A woman who is a carrier for an X-linked recessive disorder mates with an unaffected man. What is the probability that their son will be affected?

Accepted Answer

50%

Answer

0%

Answer

25%

Answer

100%

Question 3

Which type of mutation results in a premature stop codon?

Accepted Answer

Nonsense mutation

Answer

Missense mutation

Answer

Silent mutation

Answer

Frameshift mutation

Question 4

In a testcross, an individual with an unknown genotype for a single trait is crossed with a:

Accepted Answer

Homozygous recessive individual

Answer

Heterozygous individual

Answer

Homozygous dominant individual

Answer

Wild-type individual

Question 5

Which of the following is an example of codominance?

Accepted Answer

AB blood type in humans expressing both A and B antigens

Answer

A heterozygous flower producing a pink color instead of red or white

Answer

A recessive allele being completely masked by a dominant allele

Answer

Two alleles blending to produce an intermediate phenotype

Question 6

Crossing over between homologous chromosomes occurs during which phase of meiosis?

Accepted Answer

Prophase I

Answer

Metaphase I

Answer

Anaphase II

Answer

Telophase II

Question 7

Which evolutionary mechanism causes allele frequencies to change randomly due to chance events in small populations?

Accepted Answer

Genetic drift

Answer

Natural selection

Answer

Gene flow

Answer

Mutation