These polymorphic sites are referred to as RAD markers.

It is thought that these associations, and the identification of a few alleles of a haplotype sequence, can unambiguously identify all other polymorphic sites in its region.

The basic idea is that linkage disequilibrium can easily occur (for many reasons) between two (or more) polymorphic sites that are under selection.

Notice the four polymorphic sites (positions where someone differs from you, at 3, 7, 13 and 19 above).

The lower-case d described above is the difference between these two numbers-the average number of polymorphisms found in pairwise comparison (2) and the total number of polymorphic sites (4).

They described a polymorphic site near the C terminus of the coded region, but neither allele at this locus segregated consistently with the atypical trait.

An adenosine present at the polymorphic site represents the third position in a stop codon.

Other statistical approaches such as non-linear models or non-parametic tests may prove to be more sensitive when examining single polymorphisms or multiple polymorphic sites within a gene.

The most common situation arises when genotypes are collected at a set of polymorphic sites from a group of individuals.

In a single base extension method, a primer is hybridized to DNA and extended by a dideoxyribonucleoside triphosphate that matches the nucleotide at a polymorphic site.