Multipoint linkage analyses were examined for the older and younger datasets. The position and order of markers was established using a locally weighted linear regression map (http://www/qimr.edu.au/davidD) based on NCBI Build 35.1 physical map positions, deCODE and Marshfield maps. Both co-twins from MZ pairs were included in analyses (with zygosity identified), although the MZ relationship per se does not contribute to linkage. The result is similar to including one co-twin with phenotypes averaged for the pair. However, including their individual phenotypes makes clear to the model that there are two measurements, which provides added confidence. Post hoc linkage analyses examined the effects of truncating heaviness of consumption by excluding the lowest 10%, 20%, and 40% of the distribution of consumption (exact proportions, based on the Quantity × Frequency score, were 11.3%, 23.3% and 37.3% for the older dataset and 10.9%, 23.5%, and 38.3% for the younger dataset).
