Characterization of an alphoid subfamily located near p-arm sequences on human chromosome 22

The centromeric heterochromatin of all human chromosomes is composed of tan demly repeated alpha satellite DNA. Here we describe another alphoid subfam ily that maps to human chromosome 22 as determined by FISH. The alphoid seq uences were isolated from three YAC-clones carrying DNA from the pericentro meric region of the short arm of human chromosome 22 and limited amounts of alphoid DNA. This property enabled us to map the members of the subfamily to the border of the centromeric region and the short arm of the chromosome . The new alphoid subfamily may contribute to the closure of the gap remain ing between the centromeric and short-arm maps of human chromosome 22.