Chromosome Research

, Volume 10, Issue 7, pp 607–613 | Cite as

Genetic load caused by variation in the amount of rDNA in a wasp

  • S. M. S. R. Araújo
  • C. C. Silva
  • S. G. Pompolo
  • F. Perfectti
  • J. P. M. Camacho


Extensive variation in the size of the short (heterochromatic) arm of chromosome 14 was found in the wasp Trypoxylon (Trypargilum) albitarse. Ten different variants were differentiated by size and C-banding pattern. Fluorescent in-situ hybridization (FISH) revealed that ribosomal DNA in this species is clustered in the darkly C-banded parts of the heterochromatic short arm of chromosome 14. On this basis, we got an indirect estimate of the amount of rDNA from the area of these dark C-bands. The significant absence in males of the three chromosome variants with lower amounts of rDNA indicates that these three variants are lethal in this sex, and suggests the existence of a threshold marking the minimum amount of rDNA which is tolerable in haploidy. This implies about 4% genetic load in the population caused by variation in rDNA amount.

genetic load Hymenoptera nucleolus organiser rDNA Trypoxylon albitarse 


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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • S. M. S. R. Araújo
    • 1
    • 2
  • C. C. Silva
    • 1
  • S. G. Pompolo
    • 1
  • F. Perfectti
    • 2
  • J. P. M. Camacho
    • 2
  1. 1.Departamento de Biologia CelularUniversidade Estadual de Campinas (UNICAMP)Campinas, SPBrazil
  2. 2.Departamento de Genética, Facultad de CienciasUniversidad de GranadaGranadaSpain

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