Mutations in the CFTR gene result in cystic fibrosis in humans, a condition in which abnormal secretions are present in the lungs, pancreas, and sweat glands. The gene was mapped to a 500-kb region on chromosome 7 containing three candidate genes.

How would you prove that your chosen candidate is the CFTR gene?

Key Concepts

CFTR Gene Function

The CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene encodes a protein that functions as a channel for chloride ions across epithelial cell membranes. This regulation of ion transport is crucial for maintaining the balance of salt and water in various tissues, particularly in the lungs and pancreas. Mutations in the CFTR gene disrupt this function, leading to the thick, sticky mucus characteristic of cystic fibrosis.

Genetic Mapping

Genetic mapping involves identifying the location of genes on chromosomes and understanding their relationships to specific traits or diseases. In this context, mapping the CFTR gene to a 500-kb region on chromosome 7 helps narrow down potential candidate genes. Techniques such as linkage analysis and positional cloning are often used to establish these connections and identify genes associated with particular conditions.

Mutation Analysis

Mutation analysis is a method used to identify specific changes in the DNA sequence of a gene that may lead to disease. To prove that a candidate gene is the CFTR gene, researchers can perform sequencing to detect known mutations associated with cystic fibrosis. Additionally, functional assays can be conducted to assess whether the candidate gene's protein product exhibits the characteristic ion transport activity of CFTR.