Genome scan results of quantitative Social Responsiveness Scale (SRS) scores using MCLINK. The nonparametric analysis (a) does not assume a genetic model, and scores were converted to logarithm of odds (LOD) scores for ease of comparison. The parametric analysis (b), assumes the penetrance vector for an individual is based on their observed trait value and three specified trait distributions for the three genotypes at the disease locus (no risk allele, one risk allele, two risk alleles). These trait distributions are assumed to map onto the SRS score cutoffs (unaffected, spectrum, and affected). The penetrance vector for an individual is the relative probabilities of the trait being observed from the three distributions.