Background: This study aimed to investigate genetic diversity and phylogeographic structure of seven icefish populations from Yunnan freshwater lakes, Southwestern China. 
 
Methods: All 116 COI and 130 Cytb sequences from seven icefish populations were mainly used for genetic diversity, phylogeographic structure and demographic history analyses. 
 
Result: Genetic diversity analysis showed low mtDNA diversity in seven icefish populations. In the COI tree, Neosalanx sp., N. tangkahkeii and N. taihuensis samples formed a monophyletic clade with a 100% bootstrap support rate and the same occurred in the Cytb tree where our sequences, together with those of N. taihuensis and N. tangkahkeii, formed a monophyletic clade with the same high support rate. Haplotype network analysis showed that all haplotypes did not cluster separately. Genetic variation mainly occurred within populations, as revealed by the AMOVA analysis. A Mantel test proved that there was no correlation existing between genetic and geographical distances. Moreover, the entire dataset of icefish populations showed signs of population expansion. Overall, these findings suggest relatively low genetic diversity and no significant phylogeographic structure of icefish in these lakes and also imply that besides N. taihuensis, N. tangkahkeii may inhabit the seven freshwater lakes.

Genetic Diversity and Phylogeographic Structure of Icefishes (Salangidae) from Chinese Freshwater Lakes