Comparison of Transcriptome Differences in Scales of Two Closely Related Snake Species (Lycodon rufozonatus and Lycodon rosozonatus)

The diversity of skin colors observed in reptiles is indicative of their adaptation to different ecological niches, with these color variations playing essential roles in survival and reproduction. The present study focused on two closely related species (<i>Lycodon rufozonatus</i> and <i>Lycodon rosozonatus</i>) within the <i>Lycodon</i> genus that exhibit the closest color and morphological similarities. We performed RNA sequencing on the scales of both species and obtained 350,346,591 and 331,537,523 clean reads, respectively. A comparative analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases revealed that the scales of the two species exhibited similar patterns of gene enrichment. Nevertheless, the results of the PCA and the t-SNE analysis demonstrated notable differences between the scales in the diverse color variations observed in the two species. Concurrently, we conducted a comparative analysis of the skin color-related genes and the differentially expressed genes, which revealed three genes exhibiting notable disparities: RU_DN1145_c3_g2 (<i>mreg</i>), RU_DN10511_c0_g1 (<i>notch1</i>), and Unigene11172 (<i>notch1</i>). In light of the aforementioned results, we hypothesize that the discrepancy in the scale color between the two species is attributable to alterations in specific gene loci and variations in expression levels. The data presented herein provide a molecular basis for future studies on the genetic and habitat adaptation functions of scale color differences in reptiles.