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    • Keywords


      Aggregation; canalisation; development; phenotype interactions; phenotypic plasticity; quorum sensing; social selection; trishanku

    • Abstract


      In the trishanku (triA) mutant of the social amoeba Dictyostelium discoideum, aggregates are smaller than usual and the spore mass is located mid-way up the stalk, not at the apex. We have monitored aggregate territory size, spore allocation and fruiting body morphology in chimaeric groups of (quasi-wild-type) Ax2 and triA cells. Developmental canalisation breaks down in chimaeras and leads to an increase in phenotypic variation. A minority of triA cells causes largely Ax2 aggregation streams to break up; the effect is not due to the counting factor. Most chimaeric fruiting bodies resemble those ofAx2 or triA. Others are double-deckers with a single stalk and two spore masses, one each at the terminus and midway along the stalk. The relative number of spores belonging to the two genotypes depends both on the mixing ratio and on the fruiting body morphology. In double-deckers formed from 1:1 chimaeras, the upper spore mass has more Ax2 spores, and the lower spore mass more triA spores, than expected. Thus, the traits under study depend partly on the cells’ own genotype and partly on the phenotypes, and so genotypes, of other cells: they are both autonomous and non-autonomous. These findings strengthen the parallels between multicellular development and behaviour in social groups. Besides that, they reinforce the point that a trait can be associated with a genotype only in a specified context.

    • Author Affiliations


      Nameeta Mujumdar1 2 Ashvini Kumar Dubey3 Krithi Nandimath4 Vidyanand Nanjundiah1 3 4

      1. Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
      2. Division of Basic and Translational Research, University of Minnesota, Minneapolis, MN 55455, USA
      3. Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012, India
      4. Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560012, India
    • Dates

  • Journal of Biosciences | News

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