Main effects of individual common variants with associations to complex diseases have been elusive (Manolio, et al., 2009). It appears that individual samples do not possess sufficient power to detect the vast majority of common single nucleotide polymorphisms (SNPs) relevant to a given complex trait of interest. To overcome this hurdle large consortia have coordinated combined analysis over multiple studies with total sample sizes in the tens to hundreds of thousands. These massive samples have produced promising results for a number of complex traits. Perhaps the best example is with human height, where the GIANT consortium has amassed a total sample size of 183,727 Caucasians (Allen, et al., 2010). Consortia have arisen for other traits as well, such as lipid levels (Willer, et al., 2008), body mass index (Speliotes, et al., 2010) and, most important for our purposes, tobacco use (Furberg, et al., 2010; Thorgeirsson, et al., 2010).
