International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.2, 54-62 http://ecoevopublisher.com/index.php/ijmec 55 mechanisms of carnivory, metabolic thrift, and immunity. These findings not only enhance evolutionary biology but also have applied relevance to genetic improvement and conservation strategies. 2 Genetic Basis and Evolutionary Characteristics of Siniperca Species 2.1 Species composition and current research on phylogenetic relationships Siniperca is comprised of a series of freshwater species that are spread across East Asia, mainly China, with two dominant genera, Siniperca and Coreoperca. Interspecific relationships, Sinipercidae monophyly, and species boundaries have been explained through recent phylogenetic analysis using thousands of nuclear coding sequences and next-generation sequencing methods. For example, S. scherzeri has been determined to be the most basal taxon of Siniperca, and species delimitation analyses confirmed the singularity of S. chuatsi and S. kneri, within closely related species pairs. Estimates of divergence times suggest that Sinipercidae's ancestor evolved in southern China over 50 million years ago and was shaped by the subsequent historical climatic and geological events (Zhao et al., 2017). 2.2 Genetic diversity and phenotypic differentiation of germplasm resources Genetic diversity in F1 and F2 generations of interspecific hybrids between S. chuatsi and S. scherzeri is extensive, as shown by hybrids and natural populations analyses. F1 and F2 generations from the hybridization between S. chuatsi and S. scherzeri possess greater genetic diversity and extensive morphological differentiation, especially for F1 hybrids. Microsatellite and SNP analyses indicate that hybrid and backcross populations maintain intermediate or higher levels of heterozygosity than parental species, indicative of their vigorous breeding power. There are particular molecular markers used in identifying hybrids and genetic breeding schemes. Population analysis of S. scherzeri within the Pearl River drainage also identified particular genetic lineages due to vicariance and demographic history, highlighting the genetic intricacy of the genus (Zhang et al., 2022; Chen et al., 2024) (Figure 1). Figure 1 Morphology of the S. chuatsi ♀ ×S. scherzeri ♂, F1, F2, and backcross hybrids (Adopted from Chen et al., 2024) Image caption: a: S. chuatsi, b: S. scherzeri, c: F1 (CS), d: CS-C (81%), e: C-CS (19%), f: F2 large size (97%), g: F2 small size (3%) (Adopted from Chen et al., 2024) 2.3 Potential adaptive traits and mechanisms of ecological divergence Comparative and genomic studies have revealed adaptive characters and molecular routes of ecological divergence in Siniperca. Differentially expressed genes for metabolism, pigmentation, and the immune system are triggered by structural variants impacting cis-regulatory elements leading to phenotypic diversity among closely related species, e.g., S. chuatsi and S. scherzeri. Gene family expansion and positive selection are linked to features like predatory feeding, growth, and habitat tolerance. For instance, adaptive gene evolution for feeding and aggression-related genes occurs quickly, while gene family diversity for growth, immunity, and mobility explains niche preference between species like S. undulata and S. obscura. Such findings emphasize the role of genomic structure and evolution in ecological adaptation control among Siniperca species (Chen et al., 2020; Zhang et al., 2022; Jiang et al., 2023).
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