Overview
Haplogroup D0 is a very rare and still poorly understood branch within the broader D lineage. While most D lineages are concentrated in East and Southeast Asia, D0 has been reported in a small number of African individuals. This makes it unusual, because D as a whole is usually treated as a non African haplogroup that diverged from DE and then expanded eastward. The existence of D0 suggests that some D related diversity remained in Africa for a long time, or that early D carrying populations may have moved back into Africa after an initial expansion. In either case, D0 provides an important reminder that the early history of DE and D was not a simple one way movement but involved complex population structure and possibly multiple episodes of movement between regions.
Geographic distribution
The known occurrences of D0 are confined to very low frequencies in a few African populations, mainly in northeastern or eastern Africa according to limited reports. Because the number of identified carriers is extremely small and sample sizes are limited, the true geographic range of D0 is still uncertain. It is possible that D0 is restricted to a few families or local groups that have not been fully characterized yet. No significant presence of D0 has been reported outside Africa, in contrast to D1 derived lineages that dominate in Japan, Tibet and the Andaman Islands.
Ancient DNA
- There are currently no confirmed ancient Y DNA samples belonging to D0. The lineage is known only from a handful of modern individuals identified in high resolution sequencing projects.
- Because of the lack of ancient samples, interpretations of D0's history rely mainly on its position in the phylogenetic tree and its modern African distribution.
- The presence of D0 in Africa suggests that the early diversification of D may have involved populations that remained on the continent while other D lineages moved eastward.
Phylogeny & subclades
In the Y chromosome tree, D0 branches near the base of haplogroup D, separate from the better known D1 lineage that later radiated in Asia. It forms a small side branch whose internal structure is not yet well resolved due to the very small number of sequenced carriers. Future sequencing of additional African samples may clarify whether D0 contains multiple sub branches or is the remnant of a single small ancient population. Its position, close to the root of D, makes it relevant for estimating the timing and geography of the earliest splits within the D family.
- D0* (basal D0 lineages from a few African individuals)
- Possible micro branches that remain to be defined as more data appear
Notes & context
Because D0 is so rare and only recently reported, any interpretation of its history must be considered provisional. It is nonetheless an important piece of evidence that the DE and D clades had a more complex relationship with Africa than a simple model of D being exclusively non African. D0 may represent either an ancient branch that never left the continent or the trace of an early return migration from Asia. As more African genomes are sequenced, the status and structure of D0 will help refine models of how early modern human populations carrying DE and D lineages were distributed across Africa and Eurasia.
References & external links