Figure 1. Centromere DNA of different organisms. (a) Saccharomyces cerevisiae, showing DNA elements CDEI, II and III. (b) Schizosaccharomyces pombe, showing the nonrepetitive central core (cc) and various inverted repeats, including the functionally critical K-type repeats. (c) Parascaris univalens, showing the three different centromere states in which kinetochores are formed: along the entire length of the chromosome (state 1); only at the tips of the chromosome (state 2) or only in the middle euchromatic DNA before (state 3a) and after (state 3b) heterochromatin elimination and chromosome diminution. (d) Drosophila melanogaster, showing the distribution of simple repeats, transposable elements and nonrepetitive DNA within the centromere of the Dp1187 minichromosome. (e) Humans, showing -satellite DNA on a normal centromere (above) and non--satellite genomic DNA on a neocentromere (below).

Figure 2. Organization of Sa. cerevisiae centromere–kinetochore complex, showing the centromere DNA-associated complexes centred around the Cse4p:H4:SCM3 nucleosome, followed by the linker and microtubule (MT)-associated proteins. For simplicity, individual protein components are not shown in some of the complexes. Reproduced with permission from Westermann S et al. (2007) Structures and Functions of Yeast Kinetochore Complexes. Annual Review of Biochemistry: March 15.

Figure 3. Structural and functional domains of a mammalian centromere.

Figure 4. Known examples of different chromosomal rearrangements causing neocentromere formation. (a) An inverted duplication on the short arm of chromosome 20 results in an inv dup(20) chromosome carrying a neocentromere on band p12 on one of the two duplicated segments. (b) An interstitial deletion on the short arm p32p36.1 region of chromosome 1 results in a neocentromere-containing ring chromosome rder(1). (c) A fusion between a short-arm and a long-arm terminal segment of chromosome 10 results in the formation of mardel(10) with a neocentromere at band q25.