ABSTRACT

Three taxa of Bithynia snails, Bithynia funiculata, B. siamensis siamensis and B. siamensis goniomphalos, are currently recognised in Thailand. They serve as first intermediate hosts for the liver fluke Opisthorchis viverrini sensu lato. This study aims to characterise the arginine kinase gene intron regions (AKInt) for further use as molecular markers to explore the genetic variation and differentiation of Bithynia snails in Thailand. Four intron regions belonging to the AK gene, namely AK intron 1 (AKInt1) to AK intron 4 (AKInt4) were characterised for B. funiculata, B. s. siamensis and B. s. goniomphalos. Of these, AKInt1 showed a high level of genetic variability and was the most appropriate region for reliably examining the genetic variation of Bithynia species/subspecies and discriminating between them. Two different forms of AKInt1, namely AKInt1-long containing a long fragment (∼341–351 bp) and a short fragment (∼213–229 bp), and AKInt1-short containing only a short fragment, were observed. Insertions/deletions (indels) were commonly found within AKInt1 leading to observed heterozygosity. This study revealed that nucleotide polymorphism was high in the long fragment, which was observed in some specimens. The short fragment was common in all samples and can potentially be used to discriminate between Bithynia taxa.

摘要

三个类群比提尼亚蜗牛，比提尼亚funiculata，B. siamensis等siamensis等和B. siamensis等goniomphalos，在泰国是目前公认。它们是肝吸虫Opisthorchis viverrini sensu lato的第一批中间宿主。这项研究旨在表征精氨酸激酶基因内含子区域（AKInt），以进一步用作分子标记，以探索泰国Bithynia蜗牛的遗传变异和分化。B. funiculata，B. s。鉴定了属于AK基因的四个内含子区域，即AK内含子1（AKInt1）至AK内含​​子4（AKInt4）。暹罗和B. s。淋病菌。其中，AKInt1表现出高水平的遗传变异性，是可靠地检查Bithynia物种/亚种的遗传变异并对其进行区分的最合适区域。观察到两种不同形式的AKInt1，即包含一个长片段（〜341–351 bp）和一个短片段（〜213–229 bp）的AKInt1-long，以及仅包含一个短片段的AKInt1-short。通常在AKInt1中发现插入/缺失（indels），导致观察到的杂合性。这项研究表明，在长片段中核苷酸多态性很高，这在某些标本中观察到。短片段在所有样品中都很常见，可以潜在地用于区分Bithynia类群。