Gene maps illustrate the relative locations of genes on a chromosome. Which statement best describes what these maps depict?

• A. The order of genes along a chromosome
• B. The number of genes on a chromosome
• C. The sequence of nucleotides in a gene
• D. The relative locations of genes on a chromosome

Answer: (D)

Gene maps are about where genes sit in relation to one another along a chromosome. They convey the relative locations of genes, which includes how they are ordered and how far apart they tend to be, rather than the exact DNA sequence inside a gene or the total count of genes. So the best description is that these maps show the relative locations of genes on a chromosome. The nucleotide sequence (the exact base order) isn’t what a map displays, and counting genes isn’t the map’s purpose. A map’s strength lies in showing how genes are arranged in relation to each other, which is captured by the idea of relative locations.