Others using the congenic approach have consistently created congenics using C57BL/6J or another C57 substrain as the background strain. For example, Whatley et al. used a panel of 21 C57BL/6J background congenics with DBA/2J substituted regions and confirmed QTLs for 10% ethanol consumption on chromosomes 1 and 2 (Whatley et al. 1999). Gill and Boyle used a panel of 20 C57BL/6J congenic strains with substituted genetic regions of various lengths from the A/J strain to confirm provisional QTLs for 10% ethanol consumption on chromosomes 2 and 15 (Gill and Boyle 2005). Lesscher et al. also confirmed a chromosome 2 QTL using an A/J substituted region for a limited access (rather than 24-h access) ethanol drinking trait (Lesscher et al. 2009). Finally, C57BL/6ByJ quasi-congenics [these mice carry genetic passenger regions in addition to the introgressed segment; see (Bennett 2000)] with substituted regions from BALB/cJ and CXBI/ByJ strains were used to provide evidence for QTLs on chromosome 6 and 12 for the consumption of a 12% ethanol solution offered vs water (Vadasz et al. 2007).
