Gene maps are constructed using information from which of the following?

Gene maps are constructed using information from which of the following?

• A. Protein shapes
• B. Crossing-over frequencies
• C. Chromosome length
• D. Mutation rates

Answer: (B)

Gene maps are built from how often recombination occurs between genes during meiosis. The frequency of crossing over between two genes reflects how far apart they are on the chromosome: close together means rare recombination, farther apart means more frequent recombination, and when they’re far apart or on different chromosomes the recombination rate approaches 50%. By collecting these frequencies across many gene pairs, scientists determine the order and relative distances of genes on a chromosome. That’s why information from crossing-over frequencies is used to construct gene maps. Protein shapes don’t tell you gene order, chromosome length by itself doesn’t specify which genes are linked or their order, and mutation rates don’t provide reliable distances between specific genes.

Gene maps are built from how often recombination occurs between genes during meiosis. The frequency of crossing over between two genes reflects how far apart they are on the chromosome: close together means rare recombination, farther apart means more frequent recombination, and when they’re far apart or on different chromosomes the recombination rate approaches 50%. By collecting these frequencies across many gene pairs, scientists determine the order and relative distances of genes on a chromosome. That’s why information from crossing-over frequencies is used to construct gene maps. Protein shapes don’t tell you gene order, chromosome length by itself doesn’t specify which genes are linked or their order, and mutation rates don’t provide reliable distances between specific genes.