Chapter

Evolutionary Transitions to Multicellular Life

Volume 2 of the series Advances in Marine Genomics pp 335-361

Date:

Independent Emergence of Complex Multicellularity in the Brown and Red Algae

  • J. Mark CockAffiliated withUMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff Email author 
  • , Jonas CollénAffiliated withUMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff

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Abstract

Brown and red macroalgae represent two of only five eukaryotic groups that have independently evolved complex multicellularity. Compared with animals and land plants, very little is known about the molecular mechanisms underlying multicellular development in the two macroalgal groups, but the recent publication of complete genome sequences for both of these lineages has been a first step towards changing this situation. Comparisons of these genomes with those of other multicellular and unicellular organisms have identified a number of features that may be related to the transitions to complex multicellularity in these macroalgal lineages. One particularly striking feature of the brown algae, for example, is the emergence of a family of membrane-spanning receptor kinases, a class of molecules that is also thought to have been important for the transition to complex multicellularity in animals and land plants. Surprisingly, the genomes of the brown alga Ectocarpus and the red alga Chondrus are remarkably different at the structural level, despite the fact that both organisms represent lineages that have evolved multicellularity as sedentary organisms in the seashore environment. Current efforts to identify and characterise developmental regulators in macroalgae are expected to enrich comparisons with other complex multicellular lineages.

Keywords

Chondrus crispus Complex multicellularity Developmental regulators Ectocarpus Genome sequence Genome structure Macroalgae Phylogeny Receptor kinase Small RNAs