In total, 13 OPRM1 SNPs spanning a region of 81.9 Kb were genotyped in 251 individuals. DNA from these individuals had been previously genotyped for linkage analyses [64,70,71]. The 251 individuals originated from a total of 41 families, comprising of 1 to 4 generations, with an average number of seven members per family (range, 1–30). The 251 individuals within the 41 families that were genetically informative includes: 77 parent-child, 212 sibling, 26 half sibling, 8 grandparent-grandchild, 151 avuncular, and 245 cousin relative pairs [65]. Marker information including genetic map position, location within OPRM1, and minor allele frequencies within this Indian population (as well as four reference populations for comparison) are listed in Table 1. Mendelian inconsistencies were identified using PEDSTATS [88] and made up 0.03% of the data. The physical locations of and pattern of linkage disequilibrium (LD) between the 13 SNPs typed across the OPRM1 gene are schematically presented in Figure 1.
