Centromeric alphoid sequences are breakage prone resulting in pericentromeric inversion heteromorphism of qh region of chromosome 1

Structural variations in the pericentromeric region of chromosome 1 are considered the norm. We characterized a chromosome 1 with an inversion by FISH-technique and suggested that the origin of pericentromeric heteromorphisms is far more complex than previously suggested. It is postulated that similar to the centromeric alphoid DNA sequences of chromosome 9, chromosome 1 also possesses a <<breakage prone>>, centromeric domain which may be a possible cause of such inversions involving the secondary constriction region.