NOVEL STRUCTURAL ORGANIZATION OF A MUS-MUSCULUS DBA 2 CHROMOSOME SHOWS A FIXED POSITION FOR THE CENTROMERE/

Chromosome 1 of the inbred mouse strain DBA/2 shows an unusual polymor phism associated with its centromeric satellite DNA sequences. The min or satellite array has undergone amplification and is present as two b locks separated by major satellite sequences. Both minor satellite blo cks appear to carry the sequence motif necessary for CENP-B protein bi nding. Despite this apparent similarity the functional centromere, as defined by the location of CREST antigens, appears to form only within the more terminal block. The two blocks also vary in that sister chro matid association only occurs with this more terminal block.