Phylogeography and Demographic History ofAmblyomma variegatum(Fabricius) (Acari: Ixodidae), the Tropical Bont Tick

Abstract

The genetic diversity of Amblyomma variegatum (Fabricius) from four Caribbean islands and five African countries was compared by analyzing the sequences of three gene fragments, two mitochondrial (12SrDNA and D-Loop-DL), and one nuclear (intergenic transcribed spacer 2 [ITS2]). Genetic variability of the ITS2 DNA fragment consisted of only uninformative single nucleotide mutations, and therefore this gene was excluded from further analyses. Mitochondrial gene divergences among African populations and between Caribbean and African populations were very low. Nevertheless, the data suggest that A. variegatum is divided into distinct East and West African groups, the western group including all Caribbean samples. Phylogenetic analyses of the 12SrDNA and DL gene sequences showed that the West African A. variegatum clustered in a well-supported monophyletic clade, distinct from eastern paraphyletic lineages. Sequences of A. variegatum from the Caribbean were embedded in the West African clade, which supports the known West African historical origin for these ticks.

Amblyomma parvum Aragão, 1908 (Acari: Ixodidae): Phylogeography and systematic considerations

“…Tick DNA was extracted and exoskeletons were preserved for further morphological analysis following previously published protocols (Beati and Keirans, 2001;Beati et al, 2012). A small portion of the postero-lateral idiosoma of each tick was cut off using a disposable scalpel and the entire specimen was incubated overnight in 180 μl Qiagen ATL lysis buffer (Qiagen, Valencia, CA) and 40 μl of a 14.3 mg/ml solution of proteinase K (Roche Applied Sciences, Indianapolis, IN).…”

“…After complete lysis of the tick tissues and repeated vortexing, the whole exoskeleton was stored in 70% ethanol and kept as voucher specimen. The lysed tissues were further processed as previously described (Beati and Keirans, 2001;Beati et al, 2012). Five mitochondrial gene sequences, 12SrDNA (ribosomal small-subunit RNA gene sequence), 16SrDNA (ribosomal small-subunit RNA gene sequence), COI (Cytochrome oxidase subunit I), COII (Cytochrome oxidase subunit II), and d-loop (DL, control region) were amplified by using previously reported sets of primers (Barret and Hebert, 2005;Beati and Keirans, 2001;Beati et al, 2012;Mangold et al, 1998).…”

“…The lysed tissues were further processed as previously described (Beati and Keirans, 2001;Beati et al, 2012). Five mitochondrial gene sequences, 12SrDNA (ribosomal small-subunit RNA gene sequence), 16SrDNA (ribosomal small-subunit RNA gene sequence), COI (Cytochrome oxidase subunit I), COII (Cytochrome oxidase subunit II), and d-loop (DL, control region) were amplified by using previously reported sets of primers (Barret and Hebert, 2005;Beati and Keirans, 2001;Beati et al, 2012;Mangold et al, 1998). In addition, a portion of the nuclear ribosomal internal transcribed spacer 2 (ITS2) was amplified by modifying previously published methods, with 35 instead of 27 cycles of annealing (Beati et al, 2012;McLain et al, 1995).…”

Current Limitations in the Control and Spread of Ticks that Affect Livestock: A Review

“…However, it must be noted that the physiological limits of an invading organism depend upon its plasticity and the phenotype of the spreading "seeds". Amblyomma variegatum is adapted to a wide range of climate conditions in its natural distribution range [72] and it is risky to speculate about the physiological limits that the invading population can endure and how it will respond to the new climate conditions. It appears that the climate conditions of the nearby continents do not closely match the conditions that are preferred by the tick, as was previously believed.…”

Comparación y utilidad de las regiones mitocondriales de los genes 16S y COX1 para los análisis genéticos en garrapatas (Acari: Ixodidae)

“…Entre los ejemplos más notables de ajustes taxonómicos en los que los análisis genéticos han sido definitivos en la descripción de nuevas especies y en la identificación de complejos en las familias Ixodidae y Argasidae, están el complejo Rhipicephalus sanguineus (6)(7)(8), el grupo Ornithodoros talaje (9) y el complejo Amblyomma cajennense (10,11). Debido a las peculiaridades biológicas y ecológicas que presentan las diferentes especies y grupos de especies de garrapatas, los estudios genéticos se han convertido en una herramienta importante para explorar las relaciones poblaciones (8,(12)(13)(14), delimitar las especies (15)(16)(17), hacer los análisis filogenéticos (18)(19)(20), e, incluso, identificar potenciales zonas de riesgo de transmisión de enfermedades (3,7,8).…”