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Advisor(s)
Abstract(s)
Ixodes ricinus is an important vector of several human and veterinary infectious agents.
Its wide geographical distribution and permissive feeding behaviour have prompted
earlier studies on its population genetics. Results were, nevertheless, not conclusive.
Furthermore, no research has fully focused on the south-western distribution range of
I. ricinus, where exchanges between European and North African populations are more
likely to occur. The presence of an additional species, Ixodes inopinatus, in the area
further confuses the topic, as the two species are hard to differentiate morphologically.
The present work describes the testing of microsatellite markers previously described for
I. ricinus using Portuguese and Tunisian tick populations of both species. In addition,
new microsatellite loci were developed to complement the available marker toolbox.
Loci showed different amplification successes across subpopulations, with Tunisian DNA
less readily amplified. Altogether, 15 loci were considered suitable for genetic analyses
of Portuguese subpopulations, 10 for Tunisian samples, and seven, common to both
populations, were considered to be informative at the inter-continental level. A preliminary
analysis of both datasets revealed two isolated populations, which can correspond to two
different species. Furthermore, Tunisian specimens identified by sequencing of 16S
rDNA as having I. ricinus or I. inopinatus sequence profiles all clustered together in
one single population using the proposed microsatellites. This confirms that taxonomic
decisions based only on 16S rRNA gene sequencing can be misleading. The application
of the proposed set of microsatellite markers to a larger sample, representative of the
south-western Ixodes’ distribution range, will be crucial to clarify the distribution of both
species.
Description
Keywords
Ixodes ricinus Ixodes Inopinatus Mediterranean Region Microsatellites Population Genetics Infecções Sistémicas e Zoonoses
Pedagogical Context
Citation
Acarologia. 2023 Mar;63(2):356-372. doi:10.24349/bvem-4h49
Publisher
Acarologia
