Whole-genome sequence of the bovine blood fluke Schistosoma bovis supports interspecific hybridization with S. haematobium

PLoS Pathog. 2019 Jan 23;15(1):e1007513. doi: 10.1371/journal.ppat.1007513. eCollection 2019 Jan.

Abstract

Mesenteric infection by the parasitic blood fluke Schistosoma bovis is a common veterinary problem in Africa and the Middle East and occasionally in the Mediterranean Region. The species also has the ability to form interspecific hybrids with the human parasite S. haematobium with natural hybridisation observed in West Africa, presenting possible zoonotic transmission. Additionally, this exchange of alleles between species may dramatically influence disease dynamics and parasite evolution. We have generated a 374 Mb assembly of the S. bovis genome using Illumina and PacBio-based technologies. Despite infecting different hosts and organs, the genome sequences of S. bovis and S. haematobium appeared strikingly similar with 97% sequence identity. The two species share 98% of protein-coding genes, with an average sequence identity of 97.3% at the amino acid level. Genome comparison identified large continuous parts of the genome (up to several 100 kb) showing almost 100% sequence identity between S. bovis and S. haematobium. It is unlikely that this is a result of genome conservation and provides further evidence of natural interspecific hybridization between S. bovis and S. haematobium. Our results suggest that foreign DNA obtained by interspecific hybridization was maintained in the population through multiple meiosis cycles and that hybrids were sexually reproductive, producing viable offspring. The S. bovis genome assembly forms a highly valuable resource for studying schistosome evolution and exploring genetic regions that are associated with species-specific phenotypic traits.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Africa, Western
  • Animals
  • Base Sequence / genetics
  • Cattle
  • Chromosome Mapping / methods
  • DNA / genetics
  • Genome / genetics
  • Genome, Mitochondrial / genetics
  • Hybridization, Genetic / genetics*
  • Hybridization, Genetic / physiology
  • Middle East
  • Phylogeny
  • Proteome / genetics
  • Schistosoma / genetics*
  • Species Specificity
  • Trematoda / genetics
  • Whole Genome Sequencing / methods

Substances

  • Proteome
  • DNA

Grant support

This work was supported by grants from the QIMR Berghofer Medical Research Institute (Chenhall Estate) and the Australian Infectious Diseases Research Centre. NDY was supported by a National Health and Medical Research Council (NHMRC) CDF1, PKK by an NHMRC ECRF and DPM by an NHMRC SPRF (APP1102926). The work has been supported by NHMRC project grant APP1102322. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.