What is a genetic marker?

A genetic marker is defined as a specific sequence of DNA located at a known position on a chromosome. These markers can serve various purposes in genetics and medicine, including identifying the presence of certain traits, susceptibility to diseases, or assessing hereditary traits within families. Genetic markers can be single nucleotide polymorphisms (SNPs), microsatellites, or other variations in the DNA sequence that can be tracked in genetic studies.

In the context of population genetics and medical research, genetic markers are invaluable because they provide reference points that researchers can use to study the inheritance of specific traits or disease predispositions across populations. They are precisely characterized and mapped, making them reliable indicators during genetic testing and research.

The other options describe concepts that do not align with the definition of a genetic marker. For instance, a random mutation in a gene does not provide the specificity associated with a marker since it can vary widely and may not consistently correspond to known traits. Gene expression levels offer insights into how genes are turned on or off but do not pertain to the genomic location or sequence of DNA. Lastly, techniques for gene sequencing refer to methodologies used to determine the order of nucleotides in a DNA segment and are distinct from the concept of a marker itself, which relates to