PYY2 and polycystic ovary syndrome: In the PCOS group, the λ of Lasso was set to 0.05051258 (Figure 4A), and 9 genes with non-zero coefficients were identified; the top 10 genes in the random forest results were selected (Figure 4B); the SVM algorithm was used to identify the 21 genes with the smallest error (Figure 4C); finally, the Venn algorithm was used to intersect the three results, and six candidate markers (RYR3, TBC1D8B, CNST, FAM166B, SLC5A3, PYY2) were identified for the PCOS group (Figure 4D).