Phylogeny and phylogeography of medicinal leeches (genus Hirudo): fast dispersal and shallow genetic structure
Phylogenetics article published in Molecular Phylogenetics and Evolution (2012)
Abstract
Medicinal leeches (Hirudo spp.) are among the best-studied invertebrates in many aspects of their biology. Yet, relatively little is known about their biogeography, ecology and evolution. Previous studies found vast ranges but suggested low genetic diversity for some species. To examine this apparent contradiction, the phylogeny and phylogeography of the widespread Hirudo verbana, Hirudo medicinalis and Hirudo orientalis were investigated in a comparative manner. Populations from across their ranges in Europe, Asia Minor, the Caucasus and Central Asia, were analyzed by various phylogenetic and population genetic approaches using both mitochondrial (COI and 12S) and nuclear DNA sequences (ITS1, 5.8S and ITS2). The populations showed surprisingly little genetic differentiation despite vast ranges. The only clear structure was observed in H. verbana. This species is subdivided into an Eastern (southern Ukraine, North Caucasus, Turkey and Uzbekistan) and a Western phylogroup (Balkans and Italy). The two phylogroups do not overlap, suggesting distinct postglacial colonization from separate refugia. Leeches supplied by commercial facilities belong to the Eastern phylogroup of H. verbana; they originate from Turkey and the Krasnodar Territory in Russia, two leading areas of leech export. H. verbana and H. medicinalis have experienced recent rapid population growth and range expansion, while isolation by distance has shaped the genetic setup of H. orientalis. The habitat of the latter is patchy and scattered about inhospitable arid and alpine areas of Central Asia and Transcaucasia. Centuries of leech collecting and transport across Europe seem not to have affected the natural distribution of genetic diversity, as the observed patterns can be explained by a combination of historical factors and present day climatic influences.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Combined mitochondrial (COI, 12S) and nuclear (ITS1, 5.8S, ITS2) phylogeography reveals shallow genetic differentiation across vast Hirudo verbana, H. medicinalis, and H. orientalis ranges; commercial leeches originate predominantly from Turkey and the Krasnodar Territory.
Why This Matters for Hirudotherapy
This study investigated the phylogeny and phylogeography of three medicinal leech species — Hirudo verbana, H. medicinalis, and H. orientalis — using mitochondrial (COI, 12S) and nuclear DNA sequences across their ranges in Europe, Asia Minor, the Caucasus, and Central Asia. The authors found surprisingly little genetic differentiation despite vast ranges, with the only clear structure being Eastern and Western phylogroups in H. verbana, and noted that commercial leech supplies belong to the Eastern phylogroup originating from Turkey and the Krasnodar Territory. This is indirectly relevant to ASH as it informs understanding of the genetic diversity and sourcing of medicinal leech species used in therapy. The caveat is that this is a pure taxonomy/biogeography study with no direct clinical or therapeutic content.
Citation
Phylogeny and phylogeography of medicinal leeches (genus Hirudo): fast dispersal and shallow genetic structure.
Trontelj P, Utevsky SY · Molecular phylogenetics and evolution, 2012
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