title: Genetic load caused by variation in the amount of rDNA in a wasp.
abstract: 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.
authors.affiliation: Departamento de Biologia Celular, Universidade Estadual de Campinas , 13083 Campinas, SP, Brazil.
authors.forename: S M S R
authors.initials: SM
authors.lastname: Araújo
authors.forename: C C
authors.initials: CC
authors.lastname: Silva
authors.forename: S G
authors.initials: SG
authors.lastname: Pompolo
authors.forename: F
authors.initials: F
authors.lastname: Perfectti
authors.forename: J P M
authors.initials: JP
authors.lastname: Camacho
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D004275:DNA, Ribosomal / Q000235:genetics*; D004171:Diploidy; D005260:Female; D040741:Genetic Load; D014644:Genetic Variation; D006238:Haploidy; D006570:Heterochromatin; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D007814:Larva; D008297:Male; D008938:Mitosis; D012737:Sex Factors; D014863:Wasps / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal; D006570:Heterochromatin