genetic markers

A genetic marker is a known DNA sequence that can be identified by a simple assay.It can be described as some sort of variation present can arise due to mutation or alteration in the genomic loci that can be observed.A genetic marker may be a short DNA sequence, such as a sequence surrounding a single base-pair change (single nucleotide polymorphism), or a long one, like microsatellites.
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Alterations in DNA that may indicate an increased risk of developing a specific disease or disorder.