Fig. 4: Transcriptome evolution dynamics across the life cycle of Ectocarpus.

a, TAI profile across Ectocarpus life cycle stages. A lower TAI marks a transcriptome composed of evolutionarily older genes and vice versa. b, TDI profile across Ectocarpus life cycle stages. Note that the TDI captures the degree of purifying selection because it is based on the dN/dS ratio of one-to-one orthologous genes between Ectocarpus sp. 7 and Ectocarpus subulatus, >99% of which is less than 1. Thus, a lower TDI marks a transcriptome composed of genes under stronger purifying selection and vice versa. Blue lines represent male stages and red lines represent female stages. The top and bottom limits of the boxes demarcate the s.d., based on 50,000 bootstraps. Life cycle stages (x axis) are denoted as follows: GA, gametophyte; PSP, parthenosporophyte; Early, early (2–5 cell) stages; Imm, sexually immature stages; Mat, sexually mature stages.