Fig. 5.

Homoeologous expression plasticity to cope with heat stress in allotetraploid common carp. (a) Experimental design of thermal stress during embryogenesis. Seven temperatures along a gradient were set, and the 24 °C group was the control. The maximum lethal temperature for the allotetraploid embryos is 33 °C (development stopped at the gastrula stage), and the minimum lethal temperature is 12 °C (development stopped at the muscle contraction stage). (b) Overlap of homoeologous genes indicating the consistent or changeable dominant pattern under heat stress. Each row corresponds to a possible intersection: the filled-in cells show which set is part of an intersection. Purple numbers represent HGs maintaining their dominant patterns under different temperature conditions. (c) Comparison of functional enrichment for HGs with different dominant patterns under control and heat stress. GO enrichment was performed using ClusterProfiler 4.0. (d) Ka/Ks for HGs with consistent dominant patterns during development. Homoeologous gene pairs were divided into four clades according to whether their dominant patterns had changed during development. One asterisk indicates a p value < 0.05, two asterisks indicate a p value < 0.01, and three asterisks indicate a p value < 0.001. The significance was tested with a two-sided Wilcoxon rank-sum test. (e) HG dominant pattern changes under heat stress at the S3 stage. Purple depicts directional changes in the dominant patterns of HGs under heat stress. Purple in the second quadrant represents a B to A dominant change, and purple in the fourth quadrant represents a A to B dominant change. Green points represent HGs with consistent dominant patterns. Orange points represent HGs changing their patterns from dominant to balanced or from balanced to dominant under stressed conditions. (f) Examples of 16 HGs changing their dominant patterns during development and under heat stress. The 16 HGs included 9 A-to-B and 7 B-to-A HGs showing switching both during embryogenesis and under heat stress conditions. T24 represents 24 °C (control), and T30 represents heat stress.