  In eukaryote nucleosome, DNA wraps around a histone octamer in a left-handed
way. We study the process of chirality formation of nucleosome with Brownian
dynamics simulation. We model the histone octamer with a quantitatively
adjustable chirality: left-handed, right-handed or non-chiral, and simulate the
dynamical wrapping process of a DNA molecule on it. We find that the chirality
of a nucleosome formed is strongly dependent on that of the histone octamer,
and different chiralities of the histone octamer induce its different rotation
directions in the wrapping process of DNA. In addition, a very weak chirality
of the histone octamer is quite enough for sustaining the correct chirality of
the nucleosome formed. We also show that the chirality of a nucleosome may be
broken at elevated temperature.
