Table 2.

The centromere DNA–microtubule paradox

Centromere DNA	Microtubule/chromosome	Centromere DNA/microtubule (kb)	Structural pericentric DNA (kb)	Centromere region/microtubule (kb)
Budding yeast 0.125 kb	1	0.125	20	20
Fission yeast 30–40 kb	2–3	15–20	30–40	15–20
Mammalian cell 5,000 kb	25–30	165–200	1,000	33–40

The size of the centromere DNA from budding yeast to mammalian cells spans almost six orders of magnitude, from budding yeast (Fitzgerald-Hayes et al. 1982) and fission yeast (Baum et al. 1994) to mammalian cells (Willard 1990). The size of structural pericentric chromatin in budding yeast is based upon the increased concentration of cohesin around centromere (Blat and Kleckner 1999) and the organization of pericentric chromatin as proposed by Bloom et al. (2006). The number of microtubules per kinetochore ranges from one in budding yeast (O’Toole et al. 1999) to two to three in fission yeast (Ding et al. 1993) to 25–30 in newt spermatocytes (Hays and Salmon 1990). The centromere region per microtubule is the amount of structural pericentric chromatin per average microtubule number.