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Capture-based enrichment of Theileria parva DNA enables full genome assembly of first buffalo-derived strain and reveals exceptional intra-specific genetic diversity
Author(s) -
Nicholas C. Palmateer,
Kyle Tretina,
Joshua Orvis,
Olukemi O. Ifeonu,
Jonathan Crabtree,
Elliott F. Drábek,
Roger Pellé,
Elias Awino,
Hanzel T. Gotia,
James B. Munro,
Luke J. Tallon,
W. Ivan Morrison,
Claudia Daubenberger,
Vishvanath Nene,
Donald P. Knowles,
Richard P. Bishop,
Joana C. Silva
Publication year - 2020
Publication title -
plos neglected tropical diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.99
H-Index - 135
eISSN - 1935-2735
pISSN - 1935-2727
DOI - 10.1371/journal.pntd.0008781
Subject(s) - theileria parva , biology , genome , east coast fever , genetics , genetic diversity , gene , parasite hosting , single nucleotide polymorphism , nucleotide diversity , genotype , haplotype , population , demography , sociology , world wide web , computer science
Theileria parva is an economically important, intracellular, tick-transmitted parasite of cattle. A live vaccine against the parasite is effective against challenge from cattle-transmissible T . parva but not against genotypes originating from the African Cape buffalo, a major wildlife reservoir, prompting the need to characterize genome-wide variation within and between cattle- and buffalo-associated T . parva populations. Here, we describe a capture-based target enrichment approach that enables, for the first time, de novo assembly of nearly complete T . parva genomes derived from infected host cell lines. This approach has exceptionally high specificity and sensitivity and is successful for both cattle- and buffalo-derived T . parva parasites. De novo genome assemblies generated for cattle genotypes differ from the reference by ~54K single nucleotide polymorphisms (SNPs) throughout the 8.31 Mb genome, an average of 6.5 SNPs/kb. We report the first buffalo-derived T . parva genome, which is ~20 kb larger than the genome from the reference, cattle-derived, Muguga strain, and contains 25 new potential genes. The average non-synonymous nucleotide diversity ( π N ) per gene, between buffalo-derived T . parva and the Muguga strain, was 1.3%. This remarkably high level of genetic divergence is supported by an average Wright’s fixation index ( F ST ), genome-wide, of 0.44, reflecting a degree of genetic differentiation between cattle- and buffalo-derived T . parva parasites more commonly seen between, rather than within, species. These findings present clear implications for vaccine development, further demonstrated by the ability to assemble nearly all known antigens in the buffalo-derived strain, which will be critical in design of next generation vaccines. The DNA capture approach used provides a clear advantage in specificity over alternative T . parva DNA enrichment methods used previously, such as those that utilize schizont purification, is less labor intensive, and enables in-depth comparative genomics in this apicomplexan parasite.