pH in postmortem brain showed significant association with three mtDNA SNPs.

The empirical p-values were from PLINK with permutation. The three mtDNA SNPs define the super- haplogroup U, K, UK matrilineages. This super-haplogroup demonstrated significantly increased postmortem pH (mean 7.0±0.18 SD) compared to the other haplogroups combined (mean 6.8±0.18 SD); permuted p-value was 0.01 for 5,000 random group tests. This robust association was not altered by differences in PMI, agonal factors, or case-control assignment differences between haplogroups. The PMI was not different between the U, K, UK super haplogroup and the remaining haplogroups, and including PMI in ANCOVA did not reduce the significance of the pH differences (p = 0.0007 with PMI as a covariate).
*The A and G columns refer to Ingman database frequencies (URL http://www.genpat.uu.se/mtDB/), while the A# and G# columns refer to observed frequencies in this study.