Brutlag, D. L., & Peacock, W. J. (1975). In Peacock. WJ, & Brock. RD (Ed.), The eukaryote chromosome. (pp. 35-45.). Canberra Australia: Australian University Press.
Most of the highly repeated DNA of Drosophila melanogaster is composed of four species with buoyant densities 1.672,1.686, 1.688 and 1.705 g/cc in CsCI. The 1.672 satellite contains pentameric (ATAAT) and heptameric (ATATAAT) repeats. Several lines of data indicate the pentamers and heptamers are on different homogeneous molecules. Related sequences (isomers) are also found in the 1.686 satellite, the major repeat unit being AATAACATAG. A similar sequence (AGAGAAGAAG) is predominant in the 1.705 species We have no evidence for sequence heterogeneity caused by random mutation, and we Suggest that other cases of apparent sequence heterogeneity may resolve to be cases of sequence isomers, We propose that the highly repeated DNAs of any one species will show marked relatedness and that their arrangement may be important in homologous chromosome recognition.