PULSED-FIELD GEL ANALYSIS OF ALPHA-SATELLITE DNA AT THE HUMAN X-CHROMOSOME CENTROMERE - HIGH-FREQUENCY POLYMORPHISMS AND ARRAY SIZE ESTIMATE

Using pulsed-field gel analysis (PFGE), we have characterized the large array of α-satellite DNA located in the centromeric region of the human X chromosome. The tandem repetitive nature of this DNA family lends itself to examination by PFGE using restriction enzymes that cleave frequently in unique sequence DNA but which cut only rarely within the repetitive α-satellite array. Several such restriction enzymes (BglI, BglII, KpnI, ScaI) have proven highly informative in sizing the α-satellite array and in following the segregation of individual X-chromosome centromeres using PFGE polymorphisms. Among 29 different X chromosomes, α-satellite array length varied between 1380 and 3730 kb (mean = 2895 kb; SD = 537). In three large CEPH families comprising 24 meioses, inheritance of these PFGE polymorphisms was strictly Mendelian, with no indication of intraarray recombination. Such DXZ1 α-satellite polymorphisms, therefore, may prove useful in the study of pericentromeric X-linked disorders. © 1990.