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HomepageI1b2* ( Old Ix )
Variant Groups
Jim Cullen


Brief Review of the I1b2* ( Old Ix ) Subclade


The I1b2* subclade represents about four percent of haplogroup "I" and, since about seventeen percent of the world's lineages are within haplogroup "I", this means that a little over one half of one percent of the haplotypes in the world can be classified as I1b2*. Previously the term "I(x)" was used in place of "I1b2*". The change in terminology was the result of the discovery of upstream SNPs in the "I" haplotree. I(x) has since then shared the derived (positive) status of the S23 SNP with other members of the present I1b2 subclade. I1b2* is so termed since this subclade lacks the derived S24 SNP and thus all other downstream SNPs. In other words, I1b2* is defined by being negative or ancestral for all SNPs downstream of S23.

Equally defining are the Y-DNA STR repeat values for this subclade, particularly the combination of 8,10,10,12 at DYS459a,459b,455,454 which is unique in the world's modal haplotypes. I like to complete the definition by adding the 19,19 combination at YCAIIa,b. If there is one characteristic though that sets the I1b2* subclade apart from all other haplotypes in the world then it would have to be the 10,12 modal at DYS455,454. The entire rest of the world haplotree is 11,11 with either one or the other of DYS455,454 being either one step higher or one step lower. Only one subclade of one haplogroup in the entire world tree possesses the mutation on both DYS455 and 454 in this particular combination.

Traditionally, I1b2* has been divided into roughly half, based mainly on the repeat values at DYS448 and 447. According to the research Ken Nordtvedt has done on these subclades, DYS448=19 is characteristic of I1b2*-A while DYS448=21 is characteristic of I1b2*-B. Effects of diversity have produced other values usually from 18 to 22 repeats at DYS448. It can be shown that if DYS448 is 20 repeats or less then ones haplotype is likely to be I1b2*-A, especially if DYS447 is found to have 24 versus 25 repeats in conjunction with a low repeat value with DYS448. I1b2*-B is characterized by high repeat values at DYS447,448 and the modal values in this case are 25,21. More certain evaluation should be made by referring to the modal values of all available markers.


Variant Groups Within I1b2* ( Old Ix ) Subclade


In the last couple years, we have seen a boom of interest in Y-DNA STR testing and so the number of haplotypes available in the public databases has increased. I1b2* is a rare subclade but new examples have been steadily trickling in. In the past I have seen searches for I1b2* resulting in a few strange results I chalked up to random mutations. Now that the databases have grown I see that these isolated mutations are now sizable groups with the same mutations. Of course STR mutations are random and to be expected and will result in descendants with the same mutations - so there's no great surprise there. Of special interest are mutations in the slower-mutating markers since they occur infrequently and thus are useful in identifying broad groups of related lineages. In particular we will examine the DYS459a,b,455,454 combination that defines I1b2* since this is where we find the variant groups.

What I have found is that there is apparent clustering within the I1b2* subclade. I would not define them as actual clusters of I1b2* since they do not fall clearly within I1b2* based on DYS459a,b,455,454 repeats alone. I have used the term 'variants' since the defining modals are different. I1b2* as you already know is defined as an 8,10,10,12 combination at DYS459a,b,455,454. There are other groups of haplotypes readily identified as I1b2* though their repeats at DYS459a,b,455,454 are not 8,10,10,12. In order to classify these variant groups as I1b2*-A, I have simply ignored these defining modals and gathered example haplotypes based on weighted genetic distance from the I1b2*-A and I1b2*-B modal values for all other markers. I1b2* has a distinctive combination of markers even without having to refer to the classic '8,10,10,12' signature markers. This is true of any haplogroup or subclade. The results are re-examined and classified again based on the usual slow-mutating markers and any other modal shifts accompanying them.


Identifying I1b2* ( Old Ix ) Variant Haplotypes


Before I get into the analysis, I will make a small change in the way I1b2* and its variant groups are identified. If you are curious as to whether or not your haplotype may be a member of one of the variant I1b2* groups, here's how to tell. Examine your marker values For DYS459b,DYS455 which should show a combination of 9,10 or 10,10. In addition, check your repeats at YCAIIa,b which should have a combination of 19,19. H4, as reported by FTDNA, should have 9 - sometimes 10 - repeats. If one of your modals are off by one in this initial check, then take a look at your repeats for DYS389i,ii which should show a combination of 12,28; one of the lowest combinations in the world haplotree. The 9,19,19 or 10,19,19 repeats at H4,YCAIIa,b - along with the 12,28 repeats at DYS389i,ii - is actually a pretty good way to identify I1b2* in any case - standard or variant haplotypes. You can also take a look at some faster mutating markers such as DYS464a-d which I like to use to help identify I1b2* groups. You should have a combination similar to 14,14,15,15 at DYS464a-d. I find this helps since it's very rare to have differing values on all checks at the same time.

Since DYS464a-d are fast mutating markers, there will naturally be greater diversity amongst the example haplotypes. Although 14,14,15,15 is the modal for DYS464a-d for standard I1b2*, there will be a few exceptions due to natural diversity. Roughly two-thirds of all cases of I1b2* will be found to have the modal values. In most every other case, DYS464a-d will be found to be one of the following three variant combinations with roughly equal likelihood: 14,14,14,15 or 14,15,15,15 or 13,14,15,15. In my own case I happen to be an I1b2*-A with a 14,15,15,15 combination at DYS464a-d. I consider this diversity pattern to be a signature trait of I1b2* as well. A change in the diversity pattern, even if the modal values for the markers are the same, can be an important clue when it comes to tasks such as sorting subclades or uncovering variant markers as simple diversity.

For those of you with the 9,10 combination at DYS459b,455 and the 19,19 combination at YCAIIa,b you will undoubtedly find that your DYS459a,b,455,454 combination is 8,9,10,12. Congratulations, your haplotype is a member of the largest I1b2* variant group. Those of you with the 10,10 combination at DYS459b,455 who do not have the 8,10,10,12 signature that characterizes standard I1b2* will have to make an additional check. If your DYS454 has a mutation to 11 repeats instead of 12, then your haplotype is member of the second largest variant group in I1b2* and your DYS459a,b,455,454 combination will be 8,10,10,11. You will also find that DYS448 is very likely to be 19 repeats.

If your haplotype has the 10,10 combination at DYS459b,455 and the 19,19 combination at YCAIIa,b but DYS454 has not mutated from 12 repeats, then your DYS459a,b,455,454 combination will be 10,10,10,12. Your haplotype is a member of the smallest variant group in I1b2*. There are not very many examples of this last group ( just over half a dozen ) but I suspect there may also be a modal shift with DYD464a,b,c,d in this group from the standard 14,14,15,15 to a variant 14,14,14,14 but whether this trend stands up to new data remains to be seen. Marker H4, as reported by FTDNA, seems to have a modal of 10 counts instead of the usual 9. Here is a table summarizing the data:

 DYS459a,b,455,454YCAIIa,bDYS464a-dComments
Standard I1b2*8,10,10,1219,1914,14,15,15 
Variant GroupI8,9,10,1219,1914,14,15,15 
Variant GroupII8,10,10,1119,1914,14,15,15DYS448=19
Variant GroupIII10,10,10,1219,1914,14,14,14recLOH: CDY also doubled


So we see that the vast majority of the variant I1b2* haplotypes fall into three groups based on analysis of the standard set of 37 FTDNA markers.

Variant Group I
Variant Group I is the largest variant group and it is distinguished by an 8,9,10,12 combination at the defining markers. This group is a clear variant of the "I1b2*-A" subclade. After an inspection of this group, Ken Nordtvedt has come to believe that DYS459b mutated from "10" to "9" in "I1b2*-A" after it arrived in England. In the available haplotype examples we have observed, there is a clear bias to origins in England.

Variant Group II
Variant Group II is very small percentage of I1b2* and may be the result of simple diversity; this is still under investigation. DYS454 is a very slow mutating marker and simple diversity is something one doesn't normally consider with DYS454 as this marker is extremely stable in the world haplotree. However, there is a very low chance of mutation, not a zero chance. My initial impression is that this group is a fairly young one. The relative stability of the faster-mutating markers is striking, especially the solid 15,19 modal combination at DYS437,448. For most general purposes one can take a look at the diversity of DYS464a-d, even though it is a multi-copy marker, and get a general idea of the diversity of the group as a whole. All indications are that this is a young division of I1b2*.

Variant Group II is also interesting since it resembles another variant group. I1b2a*-Cont2 will normally have an 8,10,11,11 modal at DYS459a,b,455,454 but there is a small percentage that have DYS455 mutated to 10 instead of 11 and making the signature on these markers '8,10,10,11'. This causes the group to look very much like Variant Group II of I1b2*, especially since many other markers have similar repeat values. There are a couple markers you can inspect to determine which group you may belong to without having to resort to SNP testing.

 Variant I1b2a*-Cont2Variant I1b2*
DYS459a,b,455,4548,10,10,11 ( normally 8,10,11,11 )8,10,10,11 ( normally 8,10,10,12 )
DYS464a11 repeats ( low )14 repeats ( high )
DYS39212 fairly solid11 fairly solid
DYS39314 fairly solid13 ( low )
DYS389i,ii14,31 ( high and fairly stable )12,28 ( low and fairly stable )


Variant Group III
Variant Group III is apparently the result of a recLOH event based on the doubling observed in some of the multicopy markers. DYS455,454 is modal 10,12 as it should be for I(x) but DYS459a,b is modal 10,10 and DYS464a,b,c,d is modal 14,14,14,14. YCAIIa,b is modal 19,19 as would be expected. Ken has now pointed out that CDYa,b are also doubled, either 35,35 or 36,36 in the samples we have observed so far. The I(x) cluster itself is about one-half of one percent of all lineages... and Variant Group III is a small fraction of this. It's safe to say this group is very rare indeed. From all sources, we have only seven unique surname example haplotypes of this variety.


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