Genetic load caused by variation in the amount of rDNA in a wasp
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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.
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- Bohart RM, Menke AS (1976) Sphecidae Wasps of the World: A Generic Revision. Berkeley: University California Press.Google Scholar
- Imai HT, Taylor RW, Crosland MWJ, Crozier RH (1988) Modes of spontaneous chromosome mutation and karyotype evolution in ants with reference to the minimum interaction hypothesis. Jpn J Genet 63: 113-125.Google Scholar
- Miller OJ (1981) Nucleolar organisers in mammalian cells. Chromosomes Today 7: 64-73.Google Scholar
- Moreira-Filho O, Bertollo LAC, Galetti PM (1984) Structure and variability of nucleolar organizer regions in Parodontidae fish. Can J Genet Cytol. 26: 564-568.Google Scholar
- Phillips RB, Pleyte KA, Hartley SE (1988) Stock-specific differences in the number of chromosome positions of the nucleolar organizer regions in artic char (Salvelinus alpinus). Cytogenet Cell Genet 48: 9-12.Google Scholar
- Schneider S, Roessli D, Excoffier L (2000) Arlequin ver. 2.000: A software for population genetics data analysis. Genetics and Biometry Laboratory, University of Geneva, Switzerland.Google Scholar
- Schubert I, Wobus U (1985) In situ hybridisation confirms jumping nucleolus organizing region in Allium. Chromosoma 92: 143-148.Google Scholar
- Strauss SH, Tsai CH (1988) Ribosomal gene number variability in Douglas-fir. J Hered 79: 453-458.Google Scholar
- Vaughan HE, Jamilena M, Ruiz Rejón C, Parker JS, Garrido-Ramos MA (1993) Loss of nucleolar-organizer regions during polyploid evolution in Scilla autumnalis. Heredity 71: 574-580.Google Scholar
- Viégas-Péquignot E (1992) In situ hybridization to chromosomes with biotinylated probes. In: Willernson D, Ed. In situ Hybridization: A Pratical Approach. Oxford University Press pp. 137-158.Google Scholar