Fig. 4.

Sexual trait gain and loss in the volvocine algae. Branching order is of a collapsed tree inferred under maximum-likelihood analysis from an aligned amino acid, concatenated dataset of 263 nuclear genes. Numbers on branches represent bootstrap and posterior probability values, respectively. Branch lengths, corresponding to time, were inferred under the CIR relaxed clock model using 16 most clock-like genes as determined by Sortadate. Blue bars correspond to the inferred 95% HPD interval for each node. Green bubbles correspond to a sexual trait gain, and red bubbles corresponds to loss of a trait. The figure table lists the 7 mapped sexual traits and their acronyms. Pink branches denote lineages where anisogamy evolved. Members of the multicellular volvocine algae (Tetrabaenaceae, Goniaceae, and Volvocaceae) are denoted in orange, purple, and green. Taxa in black font are unicellular volvocine algae