In Drosophila melanogaster, the allele for long wings is dominant over the allele for vestigial wings, and the allele for
a gray body is dominant over the allele for a black body. A testcross was done to check for genetic linkage between the
genes for these traits, with the following results for the offspring:410
flies with long wings and a gray body 105 flies with long wings and a black body
390 flies with vestigial wings and a black body
95 flies with vestigial wings and a gray body
Which of the choices below best represents the map distance between the genes for these two traits?
a. 25.0 map units
b. 40.0 map units
c. 10.0 map units
d. 100.0 map units
e. 9.5 map units
ANSWER: a
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If both parents are homozygous for a disease-causing recessive gene, ____________________ of their children will be
affected. What will be an ideal response?
Five unknown compounds are added to water. Four of the compounds go into solution while one does not. What property does water possess that allows these four compounds to dissolve? Why might the fifth compound not dissolve?
A. The positive and negative charge in water will dissolve many substances; the substance is not structurally similar to water. B. The negative charge of water dissolves many substances; the substance is too structurally similar to water. C. The positive charge of water dissolves many substances; the substance is too structurally similar to water. D. The nonpolar quality of water dissolves many substances; the substance is not structurally similar to water.
When humans are developing in utero they have characteristics that are not found in the fully developed infant. Which type of homology does this typify?
A. Developmental. B. Structural. C. Vestigal. D. Molecular. E. Both developmental and vestigal.
The atmospheric pressure at sea level is
a. 1,000 mm Hg. b. 760 mm Hg. c. 540 mm Hg. d. 400 mm Hg. e. 320 mm Hg.