Spacer size heterogeneity in ribosomal DNA ofChironomus thummiis due to a 120 bp repeat homologous to a predominantly centromeric repeated sequence
Open Access
- 1 January 1982
- journal article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 10 (23), 7689-7700
- https://doi.org/10.1093/nar/10.23.7689
Abstract
The rDNA of Ch. tepperi is homogeneous in structure with a repeat size of 8.4 kb. This size seems to be typical for the basic repeat unit in Chironomus species. Ch. th. piger rDNA cistrons are slightly increased in length (9.0 kb). In the non-transcribed spacer (NTS) an appr. 0.18 kb segment is additionally present in about 50% of the repeats. Ch. th. thummi DNA contains largely heterogeneous rDNA repeats, mainly between 10 and 16 kb. The heterogeneity is due to varying numbers of 120 bp elements present in the NTS. The different spacer size classes are not randomly distributed. The short repetitive 120 bp elements (Cla I elements) hybridize in situ with the nucleolus and with centromere regions. The Cla I elements are regularly present in the thummi NTS, but are absent in the piger NTS. Only very few piger rDNA cistrons may contain Cla I elements.Keywords
This publication has 39 references indexed in Scilit:
- Histone gene clusters of the newt notophthalmus are separated by long tracts of satellite DNACell, 1981
- Length variation in the non-transcribed spacer of Calliphora erythrocephala ribosomal DNA is due to a 350 base-pair repeatJournal of Molecular Biology, 1981
- Chromatin structure of the histone genes of D. melanogasterCell, 1981
- Isolation and sequence organization of human ribosomal DNAJournal of Molecular Biology, 1979
- Ribosomal DNA in Drosophila melanogasterJournal of Molecular Biology, 1978
- The molecular basis for length heterogeneity in ribosomal DNA from Xenopus laevisJournal of Molecular Biology, 1976
- Detection of specific sequences among DNA fragments separated by gel electrophoresisJournal of Molecular Biology, 1975
- Unequal Crossover and the Evolution of Multigene FamiliesCold Spring Harbor Symposia on Quantitative Biology, 1974
- Spread chromosomal nucleoli of Chironomus salivary glandsExperimental Cell Research, 1973
- A membrane-filter technique for the detection of complementary DNABiochemical and Biophysical Research Communications, 1966