Mattiucci S, Cianchi R, Nascetti G, Paggi L, Sardella N, Timi J, Webb S C, Bastida R, Rodríguez D, Bullini L
Department of Public Health Sciences, Section of Parasitology, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy.
Syst Parasitol. 2003 Jan;54(1):13-23. doi: 10.1023/a:1022145926409.
Genetic variation of Contracaecum ogmorhini (sensu lato) populations from different otariid seals of the northern and southern hemisphere was studied on the basis of 18 enzyme loci as well as preliminary sequence analysis of the mitochondrial cyt b gene (260 bp). Samples were collected from Zalophus californianus in the boreal region and from Arctocephalus pusillus pusillus, A. pusillus doriferus and A. australis from the austral region. Marked genetic heterogeneity was found between C. ogmorhini (sensu lato) samples from the boreal and austral region, respectively. Two loci (Mdh-2 and NADHdh) showed fixed differences and a further three loci (Iddh, Mdh-1 and 6Pgdh) were highly differentiated between boreal and austral samples. Their average genetic distance was D(Nei) = 0.36 at isozyme level. At mitochondrial DNA level, an average proportion of nucleotide substitution of 3.7% was observed. These findings support the existence of two distinct sibling species, for which the names C. ogmorhini (sensu stricto) and C. margolisi n. sp., respectively, for the austral and boreal taxon, are proposed. A description for C. margolisi n. sp. is provided. No diagnostic morphological characters have so far been detected; on the other hand, two enzyme loci, Mdh-2 and NADHdh, fully diagnostic between the two species, can be used for the routine identification of males, females and larval stages. Mirounga leonina was found to host C. ogmorhini (s.s.) in mixed infections with C. osculatum (s.l.) (of which C. ogmorhini (s.l.) was in the past considered to be a synonym) and C. miroungae; no hybrid genotypes were found, confirming the reproductive isolation of these three anisakid species. The hosts and geographical range so far recorded for C. margolisi n. sp. and C. ogmorhini (s.s.) are given.
基于18个酶位点以及线粒体细胞色素b基因（260 bp）的初步序列分析，对来自北半球和南半球不同海狗科海豹的奥氏对盲囊线虫（广义）种群的遗传变异进行了研究。样本采集自北方地区的加州海狮以及南方地区的南美毛皮海狮指名亚种、南美毛皮海狮多里弗勒斯亚种和新西兰海狮。分别在来自北方和南方地区的奥氏对盲囊线虫（广义）样本之间发现了显著的遗传异质性。两个位点（苹果酸脱氢酶-2和NADH脱氢酶）表现出固定差异，另外三个位点（异柠檬酸脱氢酶、苹果酸脱氢酶-1和6-磷酸葡萄糖脱氢酶）在北方和南方样本之间高度分化。在同工酶水平上，它们的平均遗传距离为D（内氏）= 0.36。在线粒体DNA水平上，观察到核苷酸替换的平均比例为3.7%。这些发现支持存在两个不同的姐妹种，分别为南方类群和北方类群提出了奥氏对盲囊线虫（狭义）和马尔戈利氏对盲囊线虫新种的名称。提供了马尔戈利氏对盲囊线虫新种的描述。目前尚未检测到诊断性形态特征；另一方面，两个酶位点，苹果酸脱氢酶-2和NADH脱氢酶，在两个物种之间具有完全诊断性，可用于对雄性、雌性和幼虫阶段进行常规鉴定。发现南象海豹感染了狭义奥氏对盲囊线虫，同时混合感染了广义吻状对盲囊线虫（过去认为狭义奥氏对盲囊线虫是其同义词）和米氏对盲囊线虫；未发现杂交基因型，证实了这三种异尖科物种的生殖隔离。给出了迄今为止记录的马尔戈利氏对盲囊线虫新种和狭义奥氏对盲囊线虫的宿主及地理分布范围。
