Journal article
Identification of multilocus genetic heterogeneity in Anaplasma marginale subsp. centrale and its restriction following tick-borne transmission
Infection and immunity, Vol.81(5), pp.1852-1858
05/2013
Handle:
https://hdl.handle.net/2376/105029
PMCID: PMC3648015
PMID: 23509140
Abstract
Anaplasma marginale subsp. centrale was the first vaccine used to protect against a rickettsial disease and is still in widespread use a century later. As its use preceded development of either cryopreservation or cell culture, the vaccine strain was maintained for decades by sequential passage among donor animals, excluding the natural tick-borne transmission cycle that provides a selective pressure or population "bottleneck." We demonstrated that the vaccine strain is genetically heterogeneous at 46 chromosomal loci and that heterogeneity was maintained upon inoculation into recipient animals. The number of variants per site ranged from 2 to 11 with a mean of 2.8/locus and a mode and median of 2/locus; variants included single-nucleotide polymorphisms, insertions/deletions, polynucleotide tracts, and different numbers of perfect repeats. The genetic heterogeneity is highly unlikely to be a result of strain contamination based on analysis using a panel of eight gene markers with a high power for strain discrimination. In contrast, heterogeneity appears to be a result of genetic drift in the absence of the restriction of tick passage. Heterogeneity could be reduced following tick passage, and the reduced heterogeneity could be maintained in sequential intravenous and tick-borne passages. The reduction in vaccine strain heterogeneity following tick passage did not confer an enhanced transmission phenotype, indicating that a stochastically determined population bottleneck was likely responsible as opposed to a positive selective pressure. These findings demonstrate the plasticity of an otherwise highly constrained genome and highlight the role of natural transmission cycles in shaping and maintaining the bacterial genome.
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Details
- Title
- Identification of multilocus genetic heterogeneity in Anaplasma marginale subsp. centrale and its restriction following tick-borne transmission
- Creators
- David R Herndon - Animal Diseases Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, Washington, USAMassaro W UetiKathryn E ReifSusan M NohKelly A BraytonJoseph T AgnesGuy H Palmer
- Publication Details
- Infection and immunity, Vol.81(5), pp.1852-1858
- Academic Unit
- Veterinary Microbiology and Pathology, Department of; Paul G. Allen School for Global Animal Health
- Publisher
- United States
- Grant note
- T32 AI007025 / NIAID NIH HHS GR075800M / Wellcome Trust R01 AI044005 / NIAID NIH HHS R37 AI044005 / NIAID NIH HHS GM008336 / NIGMS NIH HHS T32 GM008336 / NIGMS NIH HHS AI044005 / NIAID NIH HHS AI07025 / NIAID NIH HHS
- Identifiers
- 99900546602601842
- Language
- English
- Resource Type
- Journal article