Genetic Variation in Schizothorax kozlovi Nikolsky in the Upper Reaches of the Chinese Yangtze River Based on Genotyping for Simplified Genome Sequencing

Abstract

Schizothorax kozlovi Nikolsky is a unique cold−water fish in the upper reaches of the Yangtze River in China and has high economic value. In our study, genetic diversity and population structure analyses were performed on seven wild populations (originating from the Jinsha River, Yalong River, and Wujiang River) in the upper reaches of the Yangtze River by genotyping by sequencing (GBS). The results indicated that a total of 303,970 single−nucleotide polymorphisms (SNPs) were identified from the seven wild populations. Lower genetic diversity was exhibited among the intrapopulations of the three tributaries, and the Wujiang River population had significant genetic differentiation when compared to the Jinsha River and Yalong River populations. Furthermore, the selected SNPs were enriched in cellular processes, environmental adaptation, signal transduction, and related metabolic processes between the Wujiang population and the other two populations. The above results indicate that the populations of S. kozlovi have different degrees of tolerance and selection pressure in response to temperature and altitude. The Wujiang intrapopulation has greater genetic diversity and differentiation than the Jinsha River and Yalong River populations, which demonstrates that the Jinsha and Yalong populations require more attention and resources for their protection. The results of this study will increase our understanding of the diversity of S. kozlovi in the upper reaches of the Yangtze River and provide a basis for the conservation and utilization of wild resources.

Population structure and adaptability analysis of Schizothorax o’connori based on whole-genome resequencing

“…In this study, the π of the seven populations of S. o’connori was low, and the PIC belonged to weak polymorphism sites. However, H O (0.2107) and H E (0.1577) were higher than those in S. kozlovi ( H O 0.09578 and H E 0.06743) [ 46 ] but lower than those in most schizothoracids, such as S. lissolabiatus ( H O 0.2695 and H E 0.2892) [ 47 ] and S. curvilabiatus ( H O 0.2489 and H E 0.2931) [ 48 ]. This may be because S. o’connori has been in a stable state after experiencing bottleneck effects and has not undergone population expansion, thus exhibiting a low pattern of genetic diversity [ 49 – 52 ].…”

Ecological Adaptations and Conservation Challenges of Schizothoracids in High Altitude Environments: A Mini Review

“…The phylogenetic diversity and evolutionary history of schizothoracids have been studied in the context of Cenozoic aridification (Abrams, 2019). The impact of historical and contemporary factors on genetic variation in Schizothorax kozlovi populations has also been explored (He, 2022). These studies underscore the urgent need for conservation efforts to protect these unique and vulnerable species.…”

Characterization of the Complete Mitochondrial Genome of Schizothorax kozlovi (Cypriniformes, Cyprinidae, Schizothorax) and Insights into the Phylogenetic Relationships of Schizothorax

“…Therefore, research on and attention to the biology of S. kozlovi are urgently needed for sustainable resource conservation. Previously, researchers have conducted studies on growth, reproduction, diet, population, and diversity [ 15 , 17 , 18 , 19 , 20 , 21 ]. But there has been little focus on the characterization of the mitochondrial genome and phylogenetic analysis for S. kozlovi .…”