Table 2.

Expansion rates at LYS2

Chromosomal alignment	Tract alterations per generation, mean (±SD)
	(CTG)25	(CAG)25
Forward	3.6 (±0.7)  × 10−5	8 (±6)  × 10−8
Reverse	1.0 (±0.2)  × 10−5	<1  × 10−8
	(CTA)24CTG	CAG(TAG)24
Reverse	<1.6  × 10−8	<1.3  × 10−8

Chromosomal alignment refers to the direction of URA3 relative to the chromosomal sequences (Fig. 1). “Forward” indicates that the URA3 reporter and the endogenous LYS2 gene are aligned in the same direction (as in Fig. 1 A and B), and “reverse” indicates opposite directions (Fig. 1 C and D).