haplogroups.info
Y-DNA Haplogroup Atlas

A · A1 · A1b · A1b1 · BT · CT · CF · F · I · I*

Basal Haplogroup I*

I-M170*

Macro-haplogroup
I
Parent clade
I
Formed (estimate)
c. 35,000–45,000 years before present
TMRCA (estimate)
paraphyletic; not a single coherent node

Overview

I* represents the paraphyletic basal layer of haplogroup I, defined by the presence of M170 and related core mutations but by the absence of the downstream marker sets that characterize I1 and I2. In practice, I* is not a single well defined clade but a category used for lineages that either sit very near the root of haplogroup I or remain insufficiently resolved by current sequencing coverage. Many putative I* samples are eventually reassigned to I1 or I2 subbranches once higher resolution data become available. From a historical perspective, basal I lineages are important because they constrain the place and time of origin of haplogroup I as a whole. They likely represent remnants of the earliest populations in which M170 rose to appreciable frequency, prior to the strong differentiation of northern European I1 and the diverse I2 radiations seen among European hunter gatherers. Although very rare in modern datasets, they preserve an echo of the initial structure of the clade.

Geographic distribution

Confirmed I* lineages are extremely rare. Tentative cases have been reported in the Balkans, Italy, the Caucasus and occasionally in the Near East, but many of these are reclassified into I2 or I1 derived clusters when high coverage sequencing is applied. A small number of individuals with ambiguous or basal I markers appear in datasets from central and southeastern Europe, reflecting either genuinely ancient lineages or simply incomplete marker resolution. Given the small sample sizes and the tendency for basal branches to be absorbed into better defined clades over time, the geographic interpretation of I* must be cautious. Nonetheless, its presence in and around Europe and the Near East is consistent with an origin of haplogroup I in this broader region.

Ancient DNA

  • Some Late Pleistocene and early Holocene European hunter gatherer genomes carry I like markers that may represent basal or near basal I lineages, although coverage often does not allow precise classification.
  • There is currently no large, well documented ancient cluster that can be firmly designated as I* rather than I1 or I2.
  • As sequencing resolution improves, some ancient samples that now appear as ambiguous I lineages may be reassigned to more precise basal branches.

Phylogeny & subclades

In the internal structure of haplogroup I, I* sits upstream of the split between I1 and I2. It represents the unresolved backbone of the clade, comprising either extinct branches or rare surviving lineages that do not share the defining SNP sets of the two main subclades. For atlas purposes, including I* highlights that the I1 and I2 radiations did not exhaust the early diversity of I, and that some lineages remained small and regionally restricted.

  • I* basal unresolved lineages
  • incipient branches ancestral to I1
  • incipient branches ancestral to I2

Notes & context

Basal I* is best understood as a technical and historical category rather than as a single cohesive ethnogeographic lineage. Explicitly displaying I* in a haplogroup atlas prevents oversimplification of the tree and allows users to see where unsorted early diversity is expected to exist.