Increased diversification rates follow shifts to bisexuality in liverworts

Research output: Contribution to journalJournal articlepeer-review

  • Benjamin Laenen
  • Machac, Antonin
  • S. Robbert Gradstein
  • Blanka Shaw
  • Jairo Patiño
  • Aurélie Désamoré
  • Bernard Goffinet
  • Cymon J. Cox
  • A. Jonathan Shaw
  • Alain Vanderpoorten

Shifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts. We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests. We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present. Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism.

Original languageEnglish
JournalNew Phytologist
Volume210
Issue number3
Pages (from-to)1121-1129
Number of pages9
ISSN1469-8137
DOIs
Publication statusPublished - 2016

    Research areas

  • Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.

ID: 169135657