Mitani H, Takahashi M, Masuyama M, Fukunaga M
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama 729-0292, Japan.
J Parasitol. 2007 Jun;93(3):719-22. doi: 10.1645/GE-953R.1.
Ixodes philipi ticks were collected from the nest burrows of streaked shearwaters, Calonectris luecomelas, on 3 different islands of Japan (Awashima: 38 degrees 45'N, 139 degrees 24'E; Mikurajima: 33 degrees 52'N, 139 degrees 36'E; and Omorijima: 36 degrees 8'N, 133 degrees 10'E). The mitochondrial cytochrome oxidase subunit I (COI) gene sequence was determined for each tick. The COI sequences of 9 other ixodid tick species also were determined, and they were used for taxonomic positioning of I. philipi. A metastriata tick, Amblyomma triguttatum, was used as an outgroup reference for the analysis. Phylogenetic examination indicated that the I. philipi ticks are on the branch with Ixodes turdus and Ixodes acutitarsus weakly, and the bootstrap value of this branching was low. Three different analyses, maximum parsimony, genetic distance, and maximum likelihood, support this conclusion. To further refine this analysis, 2761 base pairs (bp) of sequence, which included the genes for tRNA(Met), NADH dehydrogenase subunit 2 (ND2), tRNA(Trp), tRNA(Cys), tRNA(Tyr), and COI, were determined and compared for 6 I. philipi ticks from the 3 different collection sites. Although a base substitution (T to C in the ND2 gene for an Awashima tick) and 2 transitions (G to A in the COI gene for 1 Omorijima tick) have occurred, the overall sequences were highly conserved. Preserved mitochondrial sequences in the ticks from 3 widely separated locations suggest the possibility of gene flow, which was probably accomplished by migratory seabirds.
在日本的3个不同岛屿（粟岛：北纬38度45分，东经139度24分；御藏岛：北纬33度52分，东经139度36分；及大森岛：北纬36度8分，东经133度10分）上，从纹腹叉尾海燕（Calonectris luecomelas）的巢洞中采集到了菲利普硬蜱（Ixodes philipi）。对每只蜱测定了线粒体细胞色素氧化酶亚基I（COI）基因序列。还测定了其他9种硬蜱的COI序列，并将它们用于菲利普硬蜱的分类定位。选用一种具缘硬蜱（Amblyomma triguttatum）作为分析的外群参照。系统发育分析表明，菲利普硬蜱与鸫硬蜱（Ixodes turdus）和尖跗硬蜱（Ixodes acutitarsus）在分支上关系较弱，且该分支的自展值较低。最大简约法、遗传距离和最大似然法这三种不同分析均支持这一结论。为进一步完善该分析，对来自3个不同采集地点的6只菲利普硬蜱测定并比较了包括tRNA(Met)、NADH脱氢酶亚基2（ND2）、tRNA(Trp)、tRNA(Cys)、tRNA(Tyr)和COI基因在内的2761个碱基对（bp）的序列。尽管发生了一个碱基替换（粟岛一只蜱的ND2基因中T突变为C）和2个转换（大森岛一只蜱的COI基因中G突变为A），但总体序列高度保守。来自3个相距甚远地点的蜱中保存的线粒体序列提示了基因流动的可能性，这可能是由迁徙海鸟完成的。
