XRCC1 and amyotrophic lateral sclerosis: In accord with these observations, DNA ligation capacity in P-6 and P-7 spinal cord tissue extracts was reduced, compared to C-2 and C-3 extracts (Supplementary Figs. 5e, f), even though the levels of XRCC1 and LigIII were comparable in the control and ALS samples (Supplementary Figs. 5g and 5h).