Genetic Diversity And Differentiation Of Glyptothorax Zanaensis In The Nu River

The development of hydroelectricity in the Nujiang River will bring about various degrees of influences to populations of Glyptothorax zanaensis. In order to access the genetic diversity and differentiation of this species, samples in six sites in the middle and lower reach of Nujiang River were investigated using 15 polymorphic simple sequence repeats loci and mitochondrial Cyt b sequences. The main results are as follows:1. Isolation and characterization of microsatellite markersMicrosatellite markers were developed from an enriched genomic library. After library screening, 100 positive clones were sequenced. The software oligo version 6.0 was then used to design 30 pairs of primers flanking the repeat regions of interest.Here we reported 15 polymorphic microsatellites loci from a repeaten-riched genomic library. Out of these 15 polymorphic microsatellites, only 1 loci significantly deviated from Hardy-Weinberg equilibrium in the sampled population (P <0.1). These novel microsatellites provided sufficient levels of polymorphism for studing on population genetics and conservation in G. zainaensis, which may suggest population subdivision or occurrence of null alleles.2. Genetic diversity based microsatellite DNAFifteen polymorphic simple sequence repeats loci identified a total of 91 alleles in G. zainaensis. The number of alleles per locus varied from 3 (GS) to 10 (DJ) with an average of 6.1. The observed heterozygosity (Ho) value ranging from 0.892 (DJ) to 0.967 (GS), expected heterozygosity (He) value ranging from 0.553 (MN) to 0.707 (LS) and polymorphism information content (PIC) value ranging from 0.510 (DJ) to 0.644 (LS), suggesting that the genetic diversity of G. zainaensis nuclear DNA was in good condition.The genetic similarity indexes of the 6 populations varied from 0.002 to 0.999, the genetic distances from 0.131 to 0.878. The AMOVA analysis ranged from 0.012 (DJ-MN) to 0.313 (GS-DJ). Cluster’s analysis showed there were two groups. One group contained GS, GD and LS populations. DJ, MN and MC population comprised another group.3. Genetic diversity based mitochondrial Cyt b sequencesA total of 102 specimens were sampled from six sites in the middle and lower reach of Nujiang River. Eighty-seven polymorphic sites were found from the aligned sequences, and 36 haplotypes were identified among 102 specimens, none shared in all sampled sites. The haplotype diversity and nucleotide diversity were 0.851±0.028 and 0.01356±0.0008, respectively. The reconstructed neighbor-joining tree showed that haplotyes from Nujiang city (including Gongshan, Gudeng and Lushui) and Baoshan city (including Daojie, Mengnuo and Mucheng) could be grouped into two populations (Nujiang population and Baoshan population), which were supported by Analysis of Molecular variance (AMOVA) and haplotype network. It indicated that G.zainaensis in Nujiang consists of two evolutionary significant units, which warrant urgent and separate conservation efforts.