In relation to their self-nonself recognition systems (commonly referred to as mating type systems), ciliates synthesize signal molecules deputed at the control of the cell/organism switching between the asexual (mitogenic proliferation) and sexual (mating) stages of the life cycle. In the most cosmopolitan and ubiquitous ciliate, Euplotes, these molecules are represented by protein pheromones that some species constitutively diffuse into the extracellular environment, and others retain bound to the cell surface. We have determined (on the basis of SSU rRNA sequence comparisons) the phylogenetic relationships of a set of known and newly identified pheromone-secreting and pheromone-retaining Euplotes species, and found that the former species represent the earliest branches of the tree while the latter ones cluster together into the latest divergent clade. We thus concluded that pheromone secretion is ancestral in Euplotes evolution while pheromone retention represents a derived condition, and tentatively identified the cause of this evolutionary shift with a mutation that prevents pheromone genes from undergoing splicing.

Pheromone evolution in the protozoan ciliate, Euplotes: The ability to synthesize diffusible forms is ancestral and secondarily lost

VALLESI, Adriana;LUPORINI, Pierangelo
2008

Abstract

In relation to their self-nonself recognition systems (commonly referred to as mating type systems), ciliates synthesize signal molecules deputed at the control of the cell/organism switching between the asexual (mitogenic proliferation) and sexual (mating) stages of the life cycle. In the most cosmopolitan and ubiquitous ciliate, Euplotes, these molecules are represented by protein pheromones that some species constitutively diffuse into the extracellular environment, and others retain bound to the cell surface. We have determined (on the basis of SSU rRNA sequence comparisons) the phylogenetic relationships of a set of known and newly identified pheromone-secreting and pheromone-retaining Euplotes species, and found that the former species represent the earliest branches of the tree while the latter ones cluster together into the latest divergent clade. We thus concluded that pheromone secretion is ancestral in Euplotes evolution while pheromone retention represents a derived condition, and tentatively identified the cause of this evolutionary shift with a mutation that prevents pheromone genes from undergoing splicing.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11581/114425
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 25
  • ???jsp.display-item.citation.isi??? 25
social impact