Population genetic structure of the parasitic nematode Spirocerca lupi in South Africa
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Date
Authors
Greeff, Jacobus Maree
Reid, Kerry
Gagjee, Janishtha R.
Clift, Sarah Jane
De Waal, Pamela Jean
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Spirocerca lupi is a parasitic nematode of canids and occurs in most tropical and subtropical regions around the world. While its life cycle is well known, insight is lacking about its mating structure within-hosts, genetic variability and long-distance dispersal ability. These characteristics contribute significantly to the dynamics and spread of potential resistance genes, which impacts on the control of S. lupi. To evaluate the population structure and infer potential mating behaviour of S. lupi, we genotyped 130 samples at nine microsatellite loci from three geographical locations in South Africa, between 600 and 1000 km apart. These loci identified unique individuals with high levels of polymorphism suggesting that these are not newly established S. lupi populations in South Africa and that effective population sizes must be large. Population genetic analyses showed that populations are not very distinct, that worms within dogs are more similar to each other than random worms from each population, and that mating is at random within dogs. We can thus infer that the parasite is frequently transported over great distances. Even so, two genetically distinct populations could be identified. Relatedness of worms within dogs were significantly higher than between dogs and together with F-statistics suggests some non-random transmission of parasites between hosts. While mating is random within a host, parasites from a host are more likely to be related and hence an increase in homozygosity is seen. The implications of this genetic structure on parasite control are considered.
Description
Supplementary data S1: Excel file of data.
Supplementary text: The use and meaning of F-statistics.
Supplementary text: The use and meaning of F-statistics.
Keywords
Canids, Gene flow, Microsatellites, F-statistics, Population structure, Relatedness, South Africa (SA), Spirocerca lupi nematodes, Spirocerca lupi worms, Worms, Animal experiment, Population genetic structure, Parasite control, Microsatellite markers, Mating, Homozygosity, Genetic association, Genetic analysis, Gene mutation
Sustainable Development Goals
Citation
Greeff, J.M., Reid, K., Gagjee, J.R. et al. 2018, 'Population genetic structure of the parasitic nematode Spirocerca lupi in South Africa', Veterinary Parasitology, vol. 258, pp. 64-69.