QTL Mapping for Low‐Dose Ethanol Activation in the LXS Recombinant Inbred Strains

Abstract

Most mouse quantitative trait loci (QTLs) for behavioral traits have been mapped using populations of mice derived from C57BL/6J (B6) and DBA/2J (D2). It is also important to identify QTLs for behavior in populations derived from other progenitors. We report results from QTL mapping for low-dose (ethanol) locomotor activation (LDA) using the recently developed LXS recombinant inbred (RI) strains, derived from Inbred Long Sleep (ILS) and Inbred Short Sleep (ISS) progenitors. The LXS RI panel has additional genetic variation, and greater power due to a larger number of strains, compared with other RI panels and strain crosses. Mice were tested using a 3-day protocol in which activity levels were monitored for 15 minutes each day. On day 1, baseline activity was recorded; on day 2, mice were injected with saline before testing; and on day 3, mice were injected with 1.8 g/kg ethanol and tested. Several suggestive QTLs were found, on chromosomes 2, 3, 4, 7, 8, 12, and 13; 3 of these QTLs were sex-specific. Two apparently novel LDA QTLs were identified, on chromosomes 4 and 8. The other QTLs appear to replicate previously identified LDA QTLs. These replicated QTLs will be pursued in subsequent studies designed to identify candidate genes.