RSPO4 and polydactyly: A total of 151 SNP loci significantly correlated with the polydactyly trait were identified through GWAS (Figure 12, Table S2), and five genes, R-spondin 4 (RSPO4), tensin-3 (TNS3), chloride channel 7 (CLCN7), SLC52A3, and ANGPT4, were annotated to be significantly correlated with polydactyly.