Abstract
To uncover the phenomenon of genetic differentiation among populations of Sinogastromyzon puliensis in Taiwan, we sequenced the mitochondrial D-loop region from samples collected from all basins and derived genetic distances among local populations. Two major deletions were found in samples from Ta-Tu River, Cho-Shuei River and Tsen-Wen River, as referenced by the Kao-Ping River samples. The largest genetic distance between Ta-Tu River and Cho-Shuei River populations is only 1.14% nucleotides substitution. If we combine the three deletion-bearing river basins together, the genetic distance of this Central Taiwan composite is 2.07％ from the Tsen-Wen River, and 2.42％ from the Kao-Ping River population. The genetic structure of Sinogastromyzon puliensis also points to similar grouping: the Nm value between Ta-Tu River and Cho-Shuei River is 24.29, and the others among all the other populations are lower than 0.17. Obviously these populations are genetically distinct. The nucleotide diversity within the Cho-Shuei River and the Tsen-Wen River populations are the lowest among all. This result is concordant with the morphological statistics. Morphologically Sinogastromyzon puliensis may be divided into two subspecies based on the number of lateral line scales. The Tsen-Wen River and the Kao-Ping River populations belong to the southern type, while the others belong to the central type. On the other hand, despite the remarkable genetic differentiation between the Tsen-Wen River and the Kao-Ping River populations, no traits with significantly discerning resolution have been found. These two populations of the southern type can not be distinguished by morphology only.