More recently, there have been large-scale gene identification efforts that have targeted affected individuals and their family members and used systematic gene identification strategies, conducting linkage analyses to identify genomic regions likely to harbor susceptibility genes, followed by association analyses to pinpoint the specific genes (Edenberg, 2006). Most recently, these strategies have been joined by GWAS that test ~1 million markers or more across the genome (Bierut et al., 2009; Edenberg et al., 2010).
