Transcription of repetitive and unique DNA nucleotide sequences in pigeon erythroid cells with different degrees of specialization.

HnRNA fractions with sedimentation coefficients greater than 45 S isolated from pigeon bone marrow as well as from the immature and mature erythroid cells of periferal blood were hybridised with a large excess of DNA fractionated on the basis of renaturation kinetics. 58-62% of the input RNAs were recovered as RNAase-resistant hybrids. About 1/3 (20%) of bone marrow greater than 45 S RNA found in the hybrids was hybridised with the repetitive and baout 2/3 (40%) with the unique DNA sequences. In addition, a considerably smaller portion of greater than 45 S RNA from the "reticulocytes" (13%) and "erythrocytes" (approximately 6%) was hybridised with the repetitive DNA.