Y-DNA STR Marker Types
A. Single-Copy Markers
List of single-copy markers
Markers: xxxxx are single-copy Y-DNA STR markers.
Definition of single-copy markers
Single-copy markers are genetic / DNA markers that occur only once in the human genome, resulting in one allele value for the marker.
B. Multi-Copy Markers
List of multi-copy markers
Markers DYS385, DYS459, DYS464 and YCAII are multi-copy Y-DNA STR markers that typically have two copies.
Marker DYS464 can occur in 4 to 7 copies in the human genome and the method for calculating genetic distance for DYS464 differs from the method used for other multi-copy markers.
Definition of multi-copy markers
Multi-copy markers are genetic/DNA markers that occur more than once (ie more than one copy) in the human genome, resulting in different allele values for each copy. For example, the markers DYS385, DYS459 and YCAII are typically present at two different locations on the Y-chromosome; therefore, they are also termed "duplicated markers". For each multi-copy marker, the same primer pair binds to different locations on the Y-chromosome, thereby amplifying more than one region simultaneously, resulting in more than one allele value for that marker. The allele values for each copy are not reported in any specific order, as the exact order of copies cannot be determined, but typically, the smaller allele value is reported first, followed by the larger allele value.
C. Special Multi-Copy Marker DYS389
DYS389 is a special marker. Unlike other multi-copy markers, only one location is amplified. The forward primer for DYS389 binds at a specific location on the Y-chromosome, whereas the reverse primer binds at two different locations. Such amplification yields two PCR products ?the shorter DYS389I fragment and the longer DYS389II fragment.