Department of Zoology, Natural History Museum, South Kensington, Cromwell Road, London SW7 5BD, UK.
Parasit Vectors. 2008 Jun 10;1(1):15. doi: 10.1186/1756-3305-1-15.
Reliable and consistent methods are required for the identification and classification of freshwater snails belonging to the genus Bulinus (Gastropoda, Planorbidae) which act as intermediate hosts for schistosomes of both medical and veterinary importance. The current project worked towards two main objectives, the development of a cost effective, simple screening method for the routine identification of Bulinus isolates and the use of resultant sequencing data to produce a model of relationships within the group.
Phylogenetic analysis of the DNA sequence for a large section (1009 bp) of the mitochondrial gene cytochrome oxidase subunit 1 (cox1) for isolates of Bulinus demonstrated superior resolution over that employing the second internal transcribed spacer (its2) of the ribosomal gene complex. Removal of transitional substitutions within cox1 because of saturation effects still allowed identification of snails at species group level. Within groups, some species could be identified with ease but there were regions where the high degree of molecular diversity meant that clear identification of species was problematic, this was particularly so within the B. africanus group.
The sequence diversity within cox1 is such that a barcoding approach may offer the best method for characterization of populations and species within the genus from different geographical locations. The study has confirmed the definition of some accepted species within the species groups but additionally has revealed some unrecognized isolates which underlines the need to use molecular markers in addition to more traditional methods of identification. A barcoding approach based on part of the cox1 gene as defined by the Folmer primers is proposed.
需要可靠和一致的方法来识别和分类属于 Bulinus 属（腹足纲，Planorbidae）的淡水蜗牛，这些蜗牛是具有医学和兽医重要性的血吸虫的中间宿主。本项目旨在实现两个主要目标，即开发一种具有成本效益、简单的筛选方法，用于常规鉴定 Bulinus 分离株，以及利用所得测序数据生成该组内关系模型。
对 Bulinus 分离株线粒体基因细胞色素氧化酶亚基 1（cox1）的一个大片段（1009 bp）的 DNA 序列进行的系统发育分析显示，其分辨率优于核糖体基因复合物的第二个内部转录间隔区（its2）。由于饱和效应，cox1 内的转换替换被去除，但仍允许在种组水平上鉴定蜗牛。在组内，一些物种可以轻松识别，但有些区域由于分子多样性程度高，导致物种的明确鉴定存在问题，特别是在 B. africanus 组内。
cox1 内的序列多样性使得条形码方法可能是从不同地理位置鉴定属内种群和物种的最佳方法。该研究证实了一些已接受的种组内某些物种的定义，但此外还揭示了一些未被识别的分离株，这强调了需要在传统鉴定方法之外使用分子标记。提议了一种基于 Folmer 引物定义的 cox1 基因部分的条形码方法。
