DETECTION AND RESOLUTION OF CLOSELY RELATED SATELLITE DNA-SEQUENCES BY MOLECULAR-CLONING

Highly repeated satellite DNAs often consist of mixtures of DNAs with closely related repeating sequences. By cloning individual molecules we have resolved the 1.705 g/cm3 satellite DNA of Drosophila melanogaster into two distinct components: polyd A-A-G-A-G T-T-C-T-C and polyd A-A-G-A-G-A-G T-T-C-T-C-T-C. The presence of two distinct sequences within this physically homogeneous satellite DNA had not previously been detected by standard physical, chemical, or sequencing techniques. Both cloning and direct sequence analysis suggest that the five-base-pair and seven-base-pair repeating units reside on separate molecules and are not interspersed with each other. © 1979.