This statement is true.
Explanation: Positional cloning is a method used to identify genetic mutations, related to a disease . The diseased gene is selected/identified on the basis of its location on the chromosome. The method contains three steps:
First, the chromosomal area related to the disease is located with the help of linkage.
Second, mapping of that diseased genomic area is done. In this markers present in diseased gene area are identified. By mapping the initial genomic area (with which we had started in Step 1) is narrowed down to a small area (the area containing the gene). In scientific terminology, such a small area is known as “contig“.
Lastly, identification of mutations in this small genomic area is done. This part of the study is called as gene analysis.