Resolving the Placement of Haplogroup I-M223 in the Y-Chromosome
Phylogenetic Tree
T.
Evidence from four case studies is presented demonstrating
that Y Haplogroup I-M223 should properly be considered a subgroup of Haplogroup
I1, rather than as a separate Haplogroup I2 as recently proposed. Haplogroup I-M223 had not been discovered when
the 2002 Y phylogenetic tree was published by the Y-Chromosome Consortium (YCC). The first study of Haplogroup I-M223 designated
it as a subgroup of I1 and named it I1c.
A later proposed revision of the Y phylogenetic tree, however, showed
I1a and I1b as P38+ and I1c with P38-, which required Haplogroup I-M223 to be
renamed as Haplogroup I2. The present
study presents four cases in which M223+ men were shown to be also P38+, which
reunites Haplogroup I-M223 with I1a and I1b within Haplogroup I1.
Received:
Address
for correspondence: wathey@hprg.com
Introduction
Y-chromosome Haplogroup I includes
about a quarter of all northwest European men.
Its largest subgroup, I1a, is common in

Figure
1 Phylogenetic Chart for Haplogroup I according to
Rootsi et al. (2004) (simplified for clarity).
The SNP M223 had not been
discovered in 2002 when the Y-Chromosome Consortium (YCC) issued the latest
official version of the Y phylogenetic tree.
Family Tree DNA (FTDNA) in late 2004 published a revision of the
YCC-2002 structure. In this new tree,
Haplogroup I-M223 was apparently assumed to be P38- and, as such, it was
renamed as Haplogroup I2, as shown in Figure 2.

Figure
2 Haplogroup I According to FTDNA’s Proposed Revision
of the Y Phylogenetic Tree (simplified for clarity).
The current study presents
the results of testing of SNPs in four men who were known or suspected to be
members of I-M223. In all cases, they
were found to be both M223+ and P38+, demonstrating that the phylogenetic
structure of Haplogroup I as presented in Rootsi et al (2004) (see Figure 1)
is correct.
Methods
|
Table 1 – Y-STR Values* for All
Subjects
* Results are presented in the same order as
in an FTDNA report. |
Four subjects were chosen from
four different surname projects where the Y-STR values suggested strongly that
they were members of I-M223. Three subjects
had results from testing either 25 or 37 Y-STR values carried out at Family
Tree DNA (FTDNA, Houston, TX), and one from testing 45 markers at Relative
Genetics (Salt Lake City, UT). The Y-STR
values, shown in Table 1, were used with the permission of the
participants, and were known prior to the present study.
Participants in the present
study were designated as Subjects 101-104.
The subjects displayed a diverse set of Y-STR haplotypes and (where
known) geographic origin. Subject 101
has an uncertain geographic origin, but his Y-STR values are similar to I-M223 haplotypes
from northwest continental
For the present study, SNP
testing was carried out on all subjects by Ethnoancestry (
Results
The results for all of the
SNP tests from the present study are shown in Table 2. All subjects were found to be derived
(positive) for both P38 and M223. Where
additional SNP testing was done, these results are also included in Table 2 for
completeness.
Table
2 SNP Results for All Subjects, This
Study*
|
ID |
SNP
Status (+ or -) |
|||||
|
101 |
M170+ |
P38+ |
M223+ |
M253- |
P37- |
|
|
102 |
P19+* |
P38+ |
M223+* |
|
|
M284- |
|
103 |
M170+ |
P38+ |
M223+ |
M253- |
P37- |
|
|
104 |
M170+ |
P38+ |
M223+ |
M253- |
P37- |
M284+ |
*
All results are from Ethnoancestry except those marked with
an asterisk. The P19 test was carried out at FTDNA, and
one
M223 test was carried out at Trace
Genetics.
Conclusion
Since all subjects were
P38+ and M223+, the correct phylogenetic structure of Haplogroup I is shown in
the chart published by Rootsi (see Figure 1).
Thus, the alternate structure shown in Figure 2 is incorrect. Since Haplogroups I-M253, I-P37, and I-M223 are
parallel sub-clades of Haplogroup I1-P38, they are properly named I1a, I1b, and
I1c.
Electronic-Database Information
http://www.northwestanalysis.net/
Haplogroup I Information
References
Nordtvedt K (2005) Population
Varieties within Y-Haplogroup I and their Extended Modal Haplotypes. Web site, URL = http://www.northwestanalysis.net/.