Niche conservatism promotes speciation in cycads: the case of Dioon merolae (Zamiaceae) in Mexico

José Said Gutiérrez-Ortega, María Magdalena Salinas-Rodríguez, Takuro Ito, Miguel Angel Pérez-Farrera, Andrew P. Vovides, José F. Martínez, Francisco Molina-Freaner, Antonio Hernández-López, Lina Kawaguchi, Atsushi J. Nagano, Tadashi Kajita, Yasuyuki Watano, Takashi Tsuchimatsu, Yuma Takahashi, Masashi Murakami

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Niche conservatism is the tendency of lineages to retain the same niche as their ancestors. It constrains biological groups and prevents ecological divergence. However, theory predicts that niche conservatism can hinder gene flow, strengthen drift and increase local adaptation: does it mean that it also can facilitate speciation? Why does this happen? We aim to answer these questions. We examined the variation of chloroplast DNA, genome-wide single nucleotide polymorphisms, morphological traits and environmental variables across the Dioon merolae cycad populations. We tested geographical structure, scenarios of demographic history, and niche conservatism between population groups. Lineage divergence is associated with the presence of a geographical barrier consisting of unsuitable habitats for cycads. There is a clear genetic and morphological distinction between the geographical groups, suggesting allopatric divergence. However, even in contrasting available environmental conditions, groups retain their ancestral niche, supporting niche conservatism. Niche conservatism is a process that can promote speciation. In D. merolae, lineage divergence occurred because unsuitable habitats represented a barrier against gene flow, incurring populations to experience isolated demographic histories and disparate environmental conditions. This study explains why cycads, despite their ancient lineage origin and biological stasis, have been able to diversify into modern ecosystems worldwide.

Original languageEnglish
Pages (from-to)1872-1884
Number of pages13
JournalNew Phytologist
Volume227
Issue number6
DOIs
Publication statusPublished - 2020 Sep 1
Externally publishedYes

Keywords

  • Dioon merolae
  • Isthmus of Tehuantepec
  • Zamiaceae
  • aridification
  • climate change
  • cycads
  • niche conservatism

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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