Paleobiogeographical origins of and in light of new DNA sequence characteristics of from hippopotamus.

Fascioliasis is a highly pathogenic disease affecting humans and livestock worldwide. It is caused by the liver flukes transmitted by / lymnaeid snails in Europe, Asia, Africa, the Americas and Oceania, and transmitted by lymnaeids in Africa and Asia. An evident founder effect appears in genetic studies as the consequence of their spread by human-guided movements of domestic ruminants, equines and Old World camelids in the post-domestication period from the beginning of the Neolithic. Establishing the geographical origins of fasciolid expansion is multidisciplinary crucial for disease assessment. Sequencing of selected nuclear ribosomal and mitochondrial DNA markers of infecting hippopotamuses () in South Africa and their comparative analyses with and , and the two species, from Asian elephants and from Holarctic cervids, allow to draw a tuned-up evolutionary scenario during the pre-domestication period. Close sequence similarities indicate a direct derivation of and from by speciation after host capture phenomena. Phylogenetic reconstruction, genetic distances and divergence estimates fully fit fossil knowledge, past interconnecting bridges between continents, present fasciolid infection in the wild fauna, and lymnaeid distribution. The paleobiogeographical analyses suggest an origin for by transfer from primitive hippopotamuses to grazing bovid ancestors of Reduncinae, Bovinae and Alcelaphinae, by keeping the same vector in warm lowlands of southeastern Africa in the mid-Miocene, around 13.5 mya. The origin of should have occurred after capture from primitive, less amphibious hippopotamuses to mid-sized ovicaprines as the wild bezoar and the wild mouflon , and from to in cooler areas and mountainous foothills of Asian Near East in the latest Miocene to Early Pliocene, around 6.0 to 4.0 mya and perhaps shortly afterwards.