Positional Cloning

Question

Positional cloning
A) seeks regions of the genome shared by the members of large families who have the same Mendelian disorder.
B) scans and then sequences the human genome chromosome by chromosome, in size order.
C) determines the sequence of protein-encoding genes on a chromosome.
D) identifies expressed sequence tags in genes of interest.
E) cuts several copies of the human genome into pieces and aligns them to derive the overall sequence.

Accepted Answer

Positional cloning is a technique used to identify the gene responsible for a particular trait or disorder by linking it to a known genetic marker or trait through inheritance. In the case of a Mendelian disorder, positional cloning would seek regions of the genome shared by the affected family members, which could potentially lead to the identification of the disease-causing gene. Option B is incorrect because scanning and sequencing the entire genome chromosome by chromosome is not an efficient way to identify a specific gene. Option C is incorrect because determining the sequence of protein-encoding genes on a chromosome is just one step in the process of positional cloning. Option D is incorrect because the identification of expressed sequence tags (ESTs) in genes of interest is a different technique used to study gene expression. Option E is also incorrect because cutting and aligning several copies of the genome is not a common method used in positional cloning.