Phylogenetic Comparison and Splice Site Conservation of the Animal <scp>SMNDC1</scp> Gene Family

Alternative splicing is a key post-transcriptional process that generates multiple mRNAs from a single pre-mRNA through the coordinated action of the spliceosome and associated splicing factors. SMNDC1 (survival motor neuron domain containing 1) has been identified as an integral component of the spliceosome complex. Previous studies have shown that SMNDC1 is essential for splicing catalysis in vitro and plays a regulatory role in intron retention in cancer. However, the phylogenetic relationships and expression patterns of SMNDC1 across the animal kingdom have not been systematically investigated. In this study, we conducted a comprehensive phylogenetic analysis of SMNDC1 genes in animals. A total of 72 SMNDC1 genes were identified from 66 animal species. Bioinformatic analyses revealed that the gene structure and protein domains of SMNDC1 are highly conserved, with only a few species possessing gene duplications. Notably, the human SMNDC1 gene exhibits elevated expression levels in multiple cancer types, including breast, colon, and rectal cancers, suggesting its potential role in tumor development and its value as a diagnostic or therapeutic target. Overall, our findings provide a systematic overview of the SMNDC1 gene family in animals and establish a foundation for future studies exploring its molecular functions and evolutionary significance.