View Full Version : Y-DNA Tutorial : how to recognise I2b subclades from STR markers

11-04-09, 12:18
Haplogroup I2b (formerly known as I1C) is found primarily in northern Germany, the Benelux, northern France, the British Isles and Scandinavia. Many subclades have been identified recently, but few people have been tested so far.

Although most people who haven't taken a deep clade test yet are categorised as I2b*, it is doubtful that anybody is still merely I2b* nowadays. Almost everybody should belong at least to I2b1 or I2b2.

There is a way of guessing your subclade from the STR markers if you tested with a genetic genealogy company like FamilyTreeDNA.

First here is a summary of the defining mutations based on the latest ISOGG nomenclature (http://isogg.org/tree/ISOGG_HapgrpI09.html)

I2b (M436/P214/S33, P216/S30, P217/S23, P218/S32)
-I2b* -

--I2b1 (M223, P219/S24, P220/S119, P221/S120, P222/U250/S118, P223/S117)
---I2b1* -
---I2b1a (M284)
---I2b1b (M379)
---I2b1c (P78)
---I2b1d (P95)

--I2b2 (L38/S154, L39/S155, L40/S156, L65/S159)

I2b2 is the easiest to identify. I2b2 people should have the following values :

DYS392 = 11 (instead of 12 for other subclades)
DYS455 = 10 (instead of 11 for other subclades)
DYS454 = 12 (instead of 11)
YCAIIb = 19 (instead of 21)

Additionally, DYS448 ranges from 19 to 22 for I2b2, whereas I2b1 almost always has a value of 20. The various DYS448 values probably represent deeper undiscovered subclades of I2b2.

Four of the six male skeletons tested from the Bronze-age Lichtenstein Cave (http://en.wikipedia.org/wiki/Lichtenstein_Cave) in central Germany belonged to I2b2.

The subclades of I2b1 are harder to tell apart. The only subclade that can be reasonably well identified is I2b1a, which most usually (but not always) has the following values :

DYS425 = null (instead of 12)
DYS406S1 = 10 (instead of 12, 11, but sometimes also 10 for other clades)
DYS413a = 19 (instead of 21)
DYS640 = 11 (instead of 12)

I2b1c usually has DYS395S1b = 15 (instead of 16).

I2b1d may have DYS640 = 13 (instead of 12).

You can find the modal haplotypes (average STR values) for each I subclade + additional variety groupings on this page (http://dgmweb.net/genealogy/DNA/Hg-I-subclades-FTDNA-order.shtml). It also includes I1 and I2a subclades.