Modern Understandings of Inheritance

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

a. deletions 

b. nonhomologous recombination 

c. synapsis 

d. X inactivation  

Figure 13.3 In a test cross for two characteristics such as the one shown here, can the predicted frequency of recombinant offspring be 60 percent? Why or why not? 

Which of the following statements is true? a. Recombination of the body color and red/cinnabar eye alleles will occur more frequently than recombination of the alleles for wing length and aristae length. b. Recombination of the body color and aristae length alleles will occur more frequently than recombination of red/brown eye alleles and the aristae length alleles. c. Recombination of the gray/black body color and long/short aristae alleles will not occur. d. Recombination of the red/brown eye and long/short aristae alleles will occur more frequently than recombination of the alleles for wing length and body color. 

Figure $13.6$ Which of the following statements about nondisjunction is true?

a. Nondisjunction only results in gametes with $n+1$ or $n-1$ chromosomes.

b. Nondisjunction occurring during meiosis II results in $50$ percent normal gametes.

c. Nondisjunction during meiosis I results in $50$ percent normal gametes.

d. Nondisjunction always results in four different kinds of gametes 

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

a. in more males than females 

b. in more females than males

c. in males and females equally 

d. in different distributions depending on the trait 

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

a. synapsis 

b. sister chromatids 

c. chiasmata 

d. alleles 

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

a. 0

b. 0.25

c. 0.50

d. 0.75

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

a. 0

b. 0.25

c. 0.50

d. 0.75

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

a. 13p12

b. 13q12

c. 12p13

d. 12q13

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

a. more uniformity

b. more variety

c. larger yields

d. 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? 

a. V formation 

b. cruciform 

c. loop 

d. pairing would not be possible 

The genotype XXY corresponds to 

a. Klinefelter syndrome 

b. Turner syndrome 

c. Triplo-X 

d. Jacob syndrome 

By definition, a pericentric inversion includes the ________. 

a. centromere 

b. chiasma 

c. telomere 

d. synapse 

Explain how the Chromosomal Theory of Inheritance helped to advance our understanding of genetics.

If the allele encoding polydactyly (six fingers) is

dominant why do most people have five fingers?

a. Genetic elements suppress the polydactyl gene.

b. Polydactyly is embryonic lethal.

c. The sixth finger is removed at birth.

d. The polydactyl allele is very rare in the human

population.

Determine whether the function is one-to-one.

$678$$y=4x^2+65$