Figure 1

Alternative processing of the 81-MAC locus. In the center are maps of the three MAC chromosomes generated from the 81-MAC locus (after [25]), with their genes' exons indicated as blocks separated by gaps representing introns; the 3' of each gene is indicated by an arrowhead. Above, indicated by arrows and blocks, are the four Telomere Addition Site regions of the locus. Below is a diagram illustrating the "partial-digest" model, in which only some chromatids are cut at the CR-L and CR-R regions, and telomeres (signified by terminal blocks) are added to each chromosome carrying a Common Region (signified by a thick line; see text).