SNPs: Why Do We Care

Single-nucleotide polymorphism (SNP) is a new term for an old concept. Geneticists have been trying for decades to find the genetic differences among individuals. Originally phenotypes were used, then protein sequence, electrophoresis, restriction fragment polymorphisms (RFLPs), and microsatellites. With recent technologies for DNA sequencing and the detection of single-base differences, we are approaching the time when all differences in DNA sequence among individuals can be found. The next challenge is to relate these genetic differences to phenotypes such as disease risk and response to therapies.