Genetic load caused by variation in the amount of rDNA in a wasp.
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.
Araújo
S M S R
SM
Departamento de Biologia Celular, Universidade Estadual de Campinas , 13083 Campinas, SP, Brazil.
Silva
C C
CC
Pompolo
S G
SG
Perfectti
F
F
Camacho
J P M
JP
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*
D004275:DNA, Ribosomal; D006570:Heterochromatin