title: Theileria lestoquardi displays reduced genetic diversity relative to sympatric Theileria annulata in Oman.
abstract: The Apicomplexan parasites, Theileria lestoquardi and Theileria annulata, the causative agents of theileriosis in small and large ruminants, are widespread in Oman, in areas where cattle, sheep and goats co-graze. Genetic analysis can provide insight into the dynamics of the parasite and the evolutionary relationship between species. Here we identified ten genetic markers (micro- and mini-satellites) spread across the T. lestoquardi genome, and confirmed their species specificity. We then genotyped T. lestoquardi in different regions in Oman. The genetic structures of T. lestoquardi populations were then compared with previously published data, for comparable panels of markers, for sympatric T. annulata isolates. In addition, we examined two antigen genes in T. annulata (Tams1 and Ta9) and their orthologues in T. lestoquardi (Tlms1 and Tl9). The genetic diversity and multiplicity of infection (MOI) were lower in T. lestoquardi (He=0.64-0.77) than T. annulata (He=0.83-0.85) in all populations. Very limited genetic differentiation was found among T. lestoquardi and T. annulata populations. In contrast, limited but significant linkage disequilibrium was observed within regional populations of each species. We identified eight T. annulata isolates in small ruminants; the diversity and MOI were lower among ovine/caprine compared to bovine. Sequence diversity of the antigen genes, Tams1 and Ta9 in T. annulata (π=0.0733 and π=0.155 respectively), was 10-fold and 3-fold higher than the orthologous Tlms1 and Tl9 in T. lestoquardi (π=0.006 and π=0.055, respectively). Despite a comparably high prevalence, T. lestoquardi has lower genetic diversity compared to sympatric T. annulata populations. There was no evidence of differentiation among populations of either species. In comparison to T. lestoquardi, T. annulata has a larger effective population size. While genetic exchange and recombination occur in both parasite species, the extent of diversity, overall, is less for T. lestoquardi. It is, therefore, likely that T. lestoquardi evolved from an ancestor of present day T. annulata and that this occurred either once or on a limited number of occasions.
authors.affiliation: Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, P.O. Box 35, Postal Code 123, Al-Khod, Sultanate of Oman.
authors.forename: Salama
authors.initials: S
authors.lastname: Al-Hamidhi
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
authors.forename: William
authors.initials: W
authors.lastname: Weir
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
authors.forename: Jane
authors.initials: J
authors.lastname: Kinnaird
authors.affiliation: Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box 34, Postal Code 123, Al-Khod, Sultanate of Oman.
authors.forename: Mohemmed
authors.initials: M
authors.lastname: Tageledin
authors.affiliation: Research Centre in Biodiversity and Genetic Resources (CIBIO - InBIO), University of Porto, Rua Padre Armando Quintas 7, Vairão 4485-661, Portugal.
authors.forename: Albano
authors.initials: A
authors.lastname: Beja-Pereira
authors.affiliation: Immunity Division, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK.
authors.forename: Ivan
authors.initials: I
authors.lastname: Morrison
authors.affiliation: Centre for Immunity, Infection & Evolution, Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Thompson
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
authors.forename: Andy
authors.initials: A
authors.lastname: Tait
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
authors.forename: Brian
authors.initials: B
authors.lastname: Shiels
authors.affiliation: Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, P.O. Box 35, Postal Code 123, Al-Khod, Sultanate of Oman; Centre for Immunity, Infection & Evolution, Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK. Electronic address: hbabiker@squ.edu.om.
authors.forename: Hamza A
authors.initials: HA
authors.lastname: Babiker
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002417:Cattle; D005819:Genetic Markers; D014644:Genetic Variation; D018503:Genome, Protozoan; D005838:Genotype; D006041:Goats / Q000469:parasitology; D058507:Host Specificity; D015810:Linkage Disequilibrium; D018895:Microsatellite Repeats; D009850:Oman / Q000453:epidemiology; D010802:Phylogeny; D015995:Prevalence; D034561:Sheep, Domestic / Q000469:parasitology; D061350:Sympatry; D016794:Theileria / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D016796:Theileria annulata / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D013801:Theileriasis / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission
chemical_list: D005819:Genetic Markers
keywords: Evolution; Host species jump; Oman; Population genetics; Theileria annulata; Theileria lestoquardi