Review Questions

X-linked recessive traits in humans (or in Drosophila) are observed ________.

1. in more males than females
2. in more females than males
3. in males and females equally
4. in different distributions depending on the trait

The first suggestion that chromosomes may physically exchange segments came from the microscopic identification of ________.

1. synapsis
2. sister chromatids
3. chiasmata
4. alleles

Which recombination frequency corresponds to independent assortment and the absence of linkage?

1. 0
2. 0.25
3. 0.50
4. 0.75

Which recombination frequency corresponds to perfect linkage and violates the law of independent assortment?

1. 0
2. 0.25
3. 0.50
4. 0.75

Which of the following codes describes position 12 on the long arm of chromosome 13?

1. 13p12
2. 13q12
3. 12p13
4. 12q13

In agriculture, polyploid crops (like coffee, strawberries, or bananas) tend to produce ________.

1. more uniformity
2. more variety
3. larger yields
4. smaller yields

Assume a pericentric inversion occurred in one of two homologs prior to meiosis. The other homolog remains normal. During meiosis, what structure—if any—would these homologs assume in order to pair accurately along their lengths?

1. V formation
2. cruciform
3. loop
4. pairing would not be possible

The genotype XXY corresponds to

1. Klinefelter syndrome
2. Turner syndrome
3. Triplo-X
4. Jacob syndrome

Abnormalities in the number of X chromosomes tends to have milder phenotypic effects than the same abnormalities in autosomes because of ________.

1. deletions
2. nonhomologous recombination
3. synapsis
4. X inactivation

By definition, a pericentric inversion includes the ________.

1. centromere
2. chiasma
3. telomere
4. synapse