Fig. 3

Identify genes involved in cold acclimation of Songpu mirror carp and Barbless carp. (A) The number of differentially expressed genes between two groups was shown in Roman numerals. Genes involved in cold acclimation of Songpu mirror carp and Barbless carp were identified through Venn’s diagrams analysis of up-regulated genes (B) and down-regulated genes (C). Differentially expressed genes in group I represent the difference of two carp species in gene expression under normal rearing temperature at 28 °C. Differentially expressed genes in groups II and III (a, b, c, a’, b’ and c’) encode specific factors for the formation of cold acclimation in Songpu mirror carp, and those in group IV (f, g, f’ and g’) encode specific factors for the formation of cold acclimation in Barbless carp. Common factors required for the formation of cold acclimation of two carp species are encoded by differentially expressed genes that are overlapped in group III and IV (d, e, d’ and e’)