Haplogroup R1a (Y-DNA) - Historic Meanings of "R1a"

Historic Meanings of "R1a"

Further information: Conversion table for Y chromosome haplogroups

The historic naming system commonly used for R1a was inconsistent in different published sources, because it changed often, this requires some explanation.

In 2002, the Y chromosome consortium (YCC) proposed a new naming system for haplogroups, which has now become standard.(YCC 2002) In this system, names with the format "R1" and "R1a" are "phylogenetic" names, aimed at marking positions in a family tree. Names of SNP mutations can also be used to name clades or haplogroups. For example, as M173 is currently the defining mutation of R1, R1 is also R-M173, a "mutational" clade name. When a new branching in a tree is discovered, some phylogenetic names will change, but by definition all mutational names will remain the same.

The widely occurring haplogroup defined by mutation M17 was known by various names, such as "Eu19", as used in (Semino 2000) in the older naming systems. The 2002 YCC proposal assigned the name R1a to the haplogroup defined by mutation SRY1532.2. This included Eu19 (i.e. R-M17) as a subclade, so Eu19 was named R1a1. Note, SRY1532.2 is also known as SRY10831.2 The discovery of M420 in 2009 has caused a reassignment of these phylogenetic names.(Underhill 2009 and ISOGG 2012) R1a is now defined by the M420 mutation: in this updated tree, the subclade defined by SRY1532.2 has moved from R1a to R1a1, and Eu19 (R-M17) from R1a1 to R1a1a.

More recent updates recorded at the ISOGG reference webpage involve branches of R-M17, including one major branch, R-M417.

Contrasting family trees for R1a, showing the evolution of understanding of this clade

2002 Scheme proposed in (YCC 2002)	2009 Scheme as per (2009)	Latest ISOGG tree as per January 2011
As M420 went undetected, M420 lineages were classified as either R1* or R1a (SRY1532.2, also known as SRY10831.2) R1 R1* R1a SRY1532.2 (SRY10831.2) R1a* R1a1 M17, M198 R1a1* M56 R1a1a M157 R1a1b M87, M204 M64.2 R1a1c R1b M343 sibling clade to R1a	After 2009, a new layer was inserted covering all old R1a, plus its closest known relatives R1 R1* R1a R1a* R1a1 R1a1* R1a1a R1a1a* M56 R1a1a1 M157 R1a1a2 M64.2,.. R1a1a3 P98 R1a1a4 PK5 R1a1a5 M434 R1a1a6 M458 R1a1a7* M334 R1a1a7a Page68 R1a1a8 R1b M343 Sibling clade to R1a (same as before)	Latest information R1 R1a1a1 R1a1a1* M56 R1a1a1a Z280 R1a1a1g2* P278.2 R1a1a1g2a L365 R1a1a1g2b L366 R1a1a1g2c Z92 R1a1a1g2d Z284 R1a1a1g3* P278.2 R1a1a1g3a P98 R1a1a1d PK5 R1a1a1e M434 R1a1a1f Z283 R1a1a1g* M458 R1a1a1g1* M334 R1a1a1g1a L260 R1a1a1g1b Z93 R1a1a1h* L342.2 R1a1a1h1* L657 R1a1a1h1a R1b