The biology and zoogeography of the Gulf Coast tick, Amblyomma maculatum Koch, the potential vector of Ehrlichia ruminantium (Dumbler) in the United States /
Nucleotide sequence variation was examined in the 16S and 12S mitochondrial ribosomal DNA genes to determine genetic relationships among populations of Gulf Coast ticks collected from Refugio Co., Texas, Bulloch Co., Georgia, Payne Co., Oklahoma, and two sites in Osage Co., Kansas. Single strand co...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2002.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765106231&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Nucleotide sequence variation was examined in the 16S and 12S mitochondrial ribosomal DNA genes to determine genetic relationships among populations of Gulf Coast ticks collected from Refugio Co., Texas, Bulloch Co., Georgia, Payne Co., Oklahoma, and two sites in Osage Co., Kansas. Single strand conformation polymorphism (SSCP) analysis of 303-bp of the 16S and12S gene was performed to identify different haplotypes and estimate relative frequencies among 120 female ticks. Seven haplotypes were identified using the 16S gene, whereas the 12S gene contained only two haplotypes. Haplotype diversity was greatest in Kansas and three of the four haplotypes in this population were not found in samples from the other populations. The fourth haplotype was present in Texas and Oklahoma samples only. Two haplotypes were determined for Texas and Oklahoma populations, one of which was unique to Texas. The seven haplotypes identified from the 16S gene were sequenced. Phylogenetic analysis using A. variegatum Fabricius, A. cajennense Fabricius, and A. americanum L., as outgroups, revealed four clades, one of which contained the outgroups A. cajennense and A. americanum. Gulf Coast ticks from the inland populations, Oklahoma and Kansas (site two), were basal to the remaining haplotypes. Two Gulf Coast tick nymph populations, Texas and Kansas (site one) identified as the most genetically different using SSCP analysis, had similar attachment site preferences when fed on Hereford heifers. On average, 68% of the total numbers of nymphs from each population were recovered from the withers, midline, and tail-head of heifers. Data indicate that nymphs of both populations dispersed from their release sites. These populations of Gulf Coast ticks are also reproductively compatible. No significant differences were detected for the weight of engorged females, weight of egg mass, or percent hatch. Although significant differences (p<0.05) were detected for the number of preoviposition days and the conversion efficiency index (CEI) when males of the Texas population were mated with females from the Kansas population, these differences were slight. Females from the Kansas population took approximately one day longer to oviposit and converted 4.5% less body weight to egg weight when mated with males from the Texas population. |
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| Item Description: | Vita. "Major Subject: Entomology". |
| Physical Description: | xvi, 162 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 141-156). |