What is a genetic marker?

A genetic marker is best defined as a sequence of DNA that has a specific location on a chromosome and is utilized for genetic mapping. Genetic markers serve as reference points in the genome that can be identified through various techniques, allowing researchers to track the inheritance of genes associated with specific traits or diseases. Their known locations make them invaluable tools in genetics for both mapping and associating traits with specific genomic regions.

This capability to link traits to particular chromosomal locations enables scientists to investigate genetic diversity, parentage, and disease susceptibility, as well as facilitate breeding programs in agriculture and the study of complex genetic disorders in humans. Understanding these markers is crucial in fields ranging from conservation biology to medical genetics.

In contrast, the other choices describe different genetic concepts that do not align with the definition of a genetic marker: a mutation refers to changes in the DNA sequence that can lead to disease, proteins are the products of gene expression, and RNA segments coding for proteins refer to mRNA, which plays a role in protein synthesis rather than genetic mapping.