Genetic Variation (Polymorphisms)

Genetic variations are differences in DNA sequence among individuals that may underlie differences in health. Genetic variations occurring in more than 1% of a population would be considered useful polymorphisms for genetic linkage analysis. Various types of polymorphisms include:

• single nucleotide polymorphisms (SNPs)
• small-scale insertions/deletions
• polymorphic repetitive elements
• microsatellite variation

Sources:  Dictionary of Genetic Terms, part of the US Department of Energy's web site on
"Genomics and Its Impact on Medicine and Society: A 2001 Primer" and the NCBI Site Map description of dbSNP.