Tick [Genome Mapping]

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Public Health Resources Public Health Resources 2008 Tick [Genome Mapping] Amy J. Ullmann Centers for Disease Control and Prevention, Fort Collins, CO Jeffrey J. Stuart Purdue University, [email protected] Catherine A. Hill Purdue University Follow this and additional works at: https://digitalcommons.unl.edu/publichealthresources Part of the Public Health Commons Ullmann, Amy J.; Stuart, Jeffrey J.; and Hill, Catherine A., "Tick [Genome Mapping]" (2008). Public Health Resources. 108. https://digitalcommons.unl.edu/publichealthresources/108 This Article is brought to you for free and open access by the Public Health Resources at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Public Health Resources by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 8 Tick Amy J. Ullmannl, Jeffrey J. stuart2, and Catherine A. Hill2 Division of Vector Borne-Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA Department of Entomology, Purdue University, 901 West State Street, West Lafayette, IN 47907, USA e-mail:[email protected] 8.1 8.1 .I Introduction Phylogeny and Evolution of the lxodida Ticks and mites are members of the subclass Acari Ticks (subphylum Chelicerata: class Arachnida: sub- within the subphylum Chelicerata. The chelicerate lin- class Acari: superorder Parasitiformes: order Ixodi- eage is thought to be ancient, having diverged from dae) are obligate blood-feeding ectoparasites of global Trilobites during the Cambrian explosion (Brusca and medical and veterinary importance. Ticks live on all Brusca 1990). It is estimated that is has been ap- continents of the world (Steen et al. 2006). There are proximately 490-550 million years since arthropods approximately 899 species of ticks; the majority are in the subphylum Mandibulata, containing the order ectoparasites of wildlife and approximately 10% of Hexapoda (Insects), shared a common ancestor with these are recognized as disease vectors or for their species in the subphylum Chelicerata (Klompen et al. ability to cause direct damage through blood feed- 1996). Not surprisingly then, ticks differ from other ing (Jongejan and Uilenberg 2004). Ticks transmit blood-feeding arthropods in many aspects of their a greater variety of viruses, bacteria, and protozoa biology. than any other blood-feeding arthropod (Dennis and Numerous papers have reviewed the phylogeny, Piesman 2005) and are second only to mosquitoes in evolution, and historical zoogeography of ticks and terms of their medical and veterinary impact (Sonen- mites. Unfortunately,phylogenetic studies ofthe Acari shine 1991). Other forms of injury attributed to ticks have been confounded by the lack of fossil evi- include anemia, dermatosis, and toxicosis. Worldwide dence, specimens, and molecular data. The current there is growing concern because tick-borne infec- understanding of Ixodida phylogeny is represented in tious diseases are emerging and resurging (Walker Fig. 1. The suborder Parasitiformes includes the or- 1998,2005; Telford and Goethert 2004). Many aspects der Ixodida which comprises three families, namely of tick biology have been investigated at the organ- the Argasidae (soft ticks), the Ixodidae (hard ticks), ismal level. However, efforts to understand the ge- and the Nuttalliellidae (comprising a single species netic basis of host seeking and selection, attachment which has not been collected for many years). It and feeding, tick-host-pathogen interactions, devel- is generally accepted that the Ixodidae are divided opment and reproduction, and acaricide resistance into two lineages, the Prostriata which consists of have been hindered by a lack of tick nucleotide se- the single genus Ixodes (subfamily: Ixodinae) con- quence. This situation is rapidly changing with the taining approximately 249 species, and the Metas- recent initiation of large-scale sequencing efforts for triata (all other genera) which contains approxi- several tick species. There has been some effort to mately 464 species. The Prostriata are thought to be develop genetic and physical maps to support and a paraphyletic lineage, with one distinct clade com- exploit tick genomic data but further advances are prising Australasian species, and the other clade of urgently required. This chapter provides an overview non-Australasian species (Klompen et al. 1996). The of the current state of tick genomics and highlights Metastriata contains four subfamilies, namely Am- areas for future research. blyomminae, Bothriocrotoninae, Haemaphysalinae, Genome Mapping and Genomics in Animals, Volume 1 Genome Mapping and Genomics in Arthropods W. Hunter, C. Kole (Eds.) O Springer-Verlag Berlin Heidelberg 2008 lxodinae Australasian lxodes IXODIDAE IF- Other lxodes Bothriocrotoninae (Bothriocroton) 1- 1- Amblyomminae (Amblyomma) I 1- Haemaphysalinae (Haemaphysali$ Rhipicephalinae 8, Hyalomminae (Rhipicephalus,Rhipicephalus (Boophilus), Derrnacentor, Hyalomma, Nosomma, Cosmiomma, Rhipicentor, Anomalohimalaya, Margaropus) NUlTALLlELLlDAE Nuttalliellinae (Nuttalliella) ARGASIDAE Argasinae (Argas) Ornithodorinae (Ornithodoros, Carios, Otobius) Holothyrida (free-living mites) Fig. 1 Current hypothesis of the phylogeny of the subfamilies of ticks. [Reprinted from Toxicon, vol47, NA Steen, SC Barker, PF Alewood, Proteins in the saliva of the Ixodida (ticks): pharmacological features and biological significance, pp 1-20, Copyright (2006), with permission from Elsevier] and Rhipicephalinae. The evidence for Amblyomma Ixodida suggests that ticks may have evolved from indicates a paraphyletic lineage where Amblyomma scavengers and not predators. The hypothesis of from Africa form a single lineage and several sub- Steen et al. (2006) suggests that ticks evolved from genera of Amblyomma exist in South America and a saprophytic, carrion-feeding lifestyle, to an ob- Australia. Bothriocrotoninae is a recently added sub- ligate hematophagous lifestyle through behavioral, family comprised of the single genus Bothriocroton, anatomical, and salivary gland adaptations. There a basal lineage of endemic Australian ticks previ- has been little molecular analysis of the Argasidae ously classified in the genus Aponomma. The remain- to date although the morphology and systematics of ing Aponomma species are now considered Ambly- this family have been studied by Klompen (1992) and omma (Klompen et al. 2002). The position of the Klompen and Oliver (1993). Two main hypotheses Haemaphysalinae has yet to be resolved, due in part have been proposed to explain the origin of the to incomplete specimens for this genus, as well as hard ticks and their subsequent dispersal around morphological similarity to certain Amblyomma spp. the globe, both of which suggest an origin in that Hyalomminae (Barker and Murrell2004) is now con- part of Gondwana that eventually became Australia. sidered an invalid subfamily as molecular data sug- The first proposes that ticks evolved in Australia gest that it arises within the Rhipicephalinae (Barker on early amphibians in the Devonian ca. 390Mya 1998). (Dobson and Barker 1999) and the other suggests Hard ticks are thought to have evolved from that the first hard tick lived much later (120Mya) bird-feeding soft ticks similar to Argas (Black and after Australia became relatively isolated (Klompen Piesman 1994; Ribeiro et al. 2006). Klompen et al. et al. 1996). (2000) applied a total-evidence based approach Despite the importance of many Ixodes species utilizing both molecular and morphological charac- as parasites and vectors, little is known about the ters to propose that the close relationship between phylogeny of the Ixodinae and there is some debate holothyrid mites (Acari: Parasitiformes) and the as to whether the genus Ixodes is mono- or para- Chapter 8 Tick 105 phyletic (Barker and Murrell 2002; Xu et al. 2003). 1997). This complex includes the Ixodes scapularis Murrell et al. (2001) utilized a total-evidence ap- (black-legged or deer tick) and I. pacificus (west- proach to propose their hypothesis of the origin of ern black-legged tick) vectors of Lyme disease (LD) Rhipicephalinae. They speculate that the Dermacen- in the USA, southern Canada, and northern Mexico tor lineage evolved in Afrotropical forest and sub- and the I. ricinus and I. persulcatus vectors of Bor- sequently dispersed on mammals to Eurasia dur- relia in the Palearctic and Oriental regions (Xu et al. ing the Eocene (50Mya). These ticks subsequently 2003). LD is the most common vector borne disease dispersed from Eurasia to the Neartic through the in the USA. Despite federal, state, and local efforts to Bering land bridge, and from Europe via Green- prevent and control LD, a total of 23,763 cases were land during the Oligocene (35 Mya). The dispersal reported in 2002 (CDC 2002) representing an almost of the Dermacentor-Anocentorticks from the Neartic threefold increase since 1991. The average direct and to the Neotropics through the Isthmus of Panama indirect medical expenses associated with LD patient took place much later, approximately 2.5 Mya. The care are estimated at $2,970 and $5,202 respectively, Nosoma-Hyalomma lineage evolved in the Orient and which translates to a nationwide estimated annual dispersed during the Miocene (19 Mya). The lineage economic impact of approximately US $203 million of Boophilus evolved in Africa and dispersed to Eura- (in 2002 dollars) (Zhang et al. 2006). sia during

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