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Large-scale diversification without genetic isolation in nematode symbionts of figs.

Vladislav SusoyMatthias HerrmannNatsumi KanzakiMeike KrugerChau N NguyenChristian RödelspergerWaltraud RöselerChristian WeilerRobin M Giblin-DavisErik J RagsdaleRalf J Sommer
Published in: Science advances (2016)
Diversification is commonly understood to be the divergence of phenotypes accompanying that of lineages. In contrast, alternative phenotypes arising from a single genotype are almost exclusively limited to dimorphism in nature. We report a remarkable case of macroevolutionary-scale diversification without genetic divergence. Upon colonizing the island-like microecosystem of individual figs, symbiotic nematodes of the genus Pristionchus accumulated a polyphenism with up to five discrete adult morphotypes per species. By integrating laboratory and field experiments with extensive genotyping of individuals, including the analysis of 49 genomes from a single species, we show that rapid filling of potential ecological niches is possible without diversifying selection on genotypes. This uncoupling of morphological diversification and speciation in fig-associated nematodes has resulted from a remarkable expansion of discontinuous developmental plasticity.
Keyphrases
  • genome wide
  • magnetic resonance
  • genetic diversity
  • copy number
  • human health
  • climate change
  • dna methylation
  • magnetic resonance imaging
  • risk assessment
  • contrast enhanced
  • nitric oxide synthase
  • sensitive detection