MADAM and sir

[Sir123]

What is is single-nucleotide polymorphism ?
TIA

[iansmith]

Variations of single base pairs scattered throughout the human genome that serve as measures of the genetic diversity in humans. About 1 million SNPs are estimated to be present in the human genome, and SNPs are useful markers for gene mapping studies.

http://www.geneed.com/glossary/s/index.html

[Janitor]

When you say a million in the genome, does that include ones in the so-called junk DNA?

[Monique]

That would mainly include junk DNA since only 3-5% of our DNA is coding. A variation is only considered a SNP if it occurs in at least 1% of a population. SNPs make up 90% of all human genetic variation. Actually nearly 1.8 million SNPs have been characterized by the SNP consortium :)