sentence: In contrast , following 1 h of darkness , chromosome dynamics increased by two-fold , and the high levels were maintained during the entire night ( ZT15 : 0.014 ± 0.0016 ; ZT19 : 0.012 ± 0.0018 ; ZT23 : 0.01 ± 0.0011 µ m , Fig. 3d ) .