ENC of orangutan chromosome 12

Evolutionary new centromeres (ENC) reported in mammals most of times feature the complexity of a normal centromere. They, however, are hypothesized to have been seeded in an anonymous sequence and to have acquired, with time, the “normal” complexity. Evidence of this kind of seeding and details on the timing of the maturation process are lacking. We have recently described a ~400k years old ENC, present at a relatively high frequency in the orangutan population. It constituted an opportunity to gain insight on its seeding and maturation process. We first identified an individual orangutan homozygous for the neocentromere. Its genome was sequenced, and we focused our analysis on the ENC domain. No substantial variations were found. Our finding strongly indicates that the ENCs seeding was essentially epigenetic in nature.