Final answer:
A genetic marker is a nucleotide sequence that can be tracked through inheritance and serves as a landmark for genetic mapping, showing polymorphism and genetic linkage with specific traits.
Step-by-step explanation:
A genetic marker is a particular nucleotide sequence at a particular locus whose inheritance can be followed. It is often used for creating genetic maps, which are similar to road maps, with markers functioning like landmarks. A genetic marker can be a gene or a sequence on a chromosome that is associated with a specific trait and shows genetic linkage, meaning it tends to be inherited with the gene of interest.
Good genetic markers are usually polymorphic regions on the chromosome, showing variability in the population. These minor differences, such as restriction fragment length polymorphisms (RFLP), variable number of tandem repeats (VNTRs), microsatellite polymorphisms, and single nucleotide polymorphisms (SNPs), are essential for genetic mapping and for understanding genetic recombination.
In effect, they act as a crucial tool in the field of genomics, which involves the study of entire genomes and their interactions within and across species.