Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psych iatrically diagnosed Finnish males. Haplotypes were constructed for 359 ind ividuals using alleles at eight loci (seven microsatellite loci and a nucle otide substitution in the DYZ3 alphoid satellite locus). A cladogram linkin g the 102 observed haplotype configurations was constructed by using parsim ony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for associat ion between Y haplotype and alcohol dependence. Finally, using only alcohol -dependent subjects, we tested for association between Y haplotype and pers onality variables postulated to define subtypes of alcoholism-antisocial pe rsonality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y ha plotype clades, with significance levels of P = 0.002, P = 0.020, and P = 0 .010, Within alcohol-dependent subjects, no relationship was revealed betwe en Y haplotype and antisocial personality disorder, novelty seeking, harm a voidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contrib ute to variation in vulnerability to alcohol dependence. However, they do n ot demonstrate an association between Y haplotype and the personality varia bles thought to underlie the subtypes of alcoholism.