Overview
H* represents the paraphyletic basal portion of haplogroup H, defined by the presence of M69 but lacking the downstream mutations that define H1, H2 or H3. These lineages either belong to branches that are extinct, poorly sampled or not yet fully resolved by modern sequencing efforts. H* is therefore not a single coherent branch but a placeholder category for early M69 derived chromosomes that fall outside the well established subclades.
Basal H lineages help illuminate the initial diversification of H within South Asia. They form the backdrop against which later expansions took place and signal the existence of ancestral diversity that has been largely absorbed by demographic expansions of H1 and the ancient but less numerous H2 and H3 branches.
Geographic distribution
Modern occurrences of true H* are extremely rare. Tentative assignments come from isolated individuals in South Asia, primarily tribal and geographically remote communities. Occasional H* like signals have been observed in Iran, Afghanistan and the Himalayan foothills but often resolve into downstream branches when full sequencing is applied. The scarcity of H* today likely reflects a combination of genetic drift, founder effects and the expansion of H1 derived lineages across much of South Asia.
Ancient DNA
- Some early Holocene and Neolithic South Asian samples may represent basal H chromosomes, though incomplete coverage prevents exact placement.
- The existence of H2 in Neolithic Anatolia suggests that basal H diversity once extended beyond the subcontinent before later contractions.
Phylogeny & subclades
In the H framework, H* sits upstream of all major subclades. It represents the unresolved backbone from which H1 (M52), H2 (P96) and H3 emerge. Retaining H* as an explicit category in an atlas preserves the phylogenetic depth of the clade and prevents the false impression that all early H lineages have been subsumed into the better defined branches.
- H* basal unresolved lineages
- ascendant nodes leading to H1, H2 and H3
Notes & context
H* is necessary for a complete atlas because it captures the earliest stages of H diversification. Even if represented by few modern individuals, its existence contextualizes the deeper structure of the clade.
References & external links