As follow-up on the common signals obtained with parametric and VC methods, we analyzed chromosomes 2, 17, and 20 using MCMC methods. Using sex- and age-adjusted joint linkage and segregation analysis, evidence of linkage for maximum number of cigarettes smoked per day was not seen on chromosome 17. However, signals were identified on chromosomes 2 and 20, with IRs of less than 2.0 at approximately 149 cM on chromosome 2, and approximately 12.0 at 65 cM on chromosome 20. Figure 2 displays MCMC intensity ratios with VC and parametric LOD scores for chromosome 20 where multiple analyses revealed peaks between 65 and 84 cM.
