A genome-wide association study to identify the genes associated with growth-related traits in Tegillarca granosa

The blood clam Tegillarca granosa is a commercially important bivalve species that is extensively cultivated worldwide. However, understanding of the molecular mechanisms underlying the growth of this species remains limited. In this study, we conducted genome-wide association studies on the growth traits of T. granosa, including shell and body weight characteristics, using a population of 300 T. granosa individuals. Correlation analysis revealed strong positive associations among the growth traits, with the exception of dressing percentage, sug-gesting that selective breeding for any of these traits can contribute to overall growth enhancement in T. granosa. A total of 39 single nucleotide polymorphism (SNP) markers associated with the seven growth traits were identified. Further investigation led to the identification of 27 candidate genes located within a 100 kb region upstream or downstream of these SNPs, which are potentially involved in T. granosa growth. Enrichment analysis of the candidate genes highlighted the biological process of transmembrane transport and the pathways related to immune system function, protein family metabolism, and JAK-STAT signaling as potential contributors to T. granosa growth. Furthermore, we discovered a haploblock associated with shell width, and validated the differential expression of four genes (Vha26, Ptprt, Stat5b, and Kmt2c) between fast and slow growing groups, which may play important roles in the growth of T. granosa. Overall, our study presents valuable genetic re-sources and serves as a reference for future marker-assisted selection strategies for enhancing the growth performance of T. granosa.