Deletions are chromosomal aberrations in which some portion of a chromosome is missing. Describe a method using Drosophila deletions to determine the actual, physical location of a gene
What will be an ideal response?
Cross homozygous mutant flies to homozygous wild-type flies that have been irradiated (or those with a series of known deletions). Select mutant flies in the F1. Those of the F1 that display the mutant phenotype may have resulted from the wild-type allele being deleted by the X-ray treatment. Establish a stock of the exceptional mutant fly; then examine polytene chromosomes in larvae. The mutation in question may be contained in the compensation loop in the homolog of the deleted chromosome. If a series of known deletions is available (and these do exist in stock centers throughout the world), one can test (by the mating described above) the mutation against each deletion. Obviously, this would be a time-consuming task unless one had some prior knowledge as to the general location of the mutant gene. This can be accomplished using balancer chromosomes and standard linkage determination. Once the mutant gene is "exposed" by a given deletion, a series of additional deletions can be used to "fine map" the region and determine a fairly accurate location for the gene.
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In photosynthesis, water + __________ = sugars
a. carbon dioxide b. nitrogen gas c. oxygen d. both carbon dioxide and oxygen
Four of the five processes listed below are associated
with the light-independent reactions. Select the exception. a. use of ATP and NADPH b. carbon fixation c. production of PGA d. the Calvin-Benson cycle e. reduction of NADP+
Which of the following statements is TRUE?
a. Once a person reaches maturity, cell division stops except to repair wounds. b. Cell division in an adult signifies cancer. c. Some specific cells throughout the body retain the ability to divide and replace themselves. d. Mitosis always produces haploid cells. e. All cells retain the ability to divide even after the organism reaches maturity.
Which of the following statements is true of bacterial plasmids?
A. They are always found in the nucleoid. B. They can replicate autonomously. C. They carry genes for essential metabolic functions. D. They are small circular DNA molecules. E. They are small circular DNA molecules that can replicate autonomously.