Complex Traits. Most neurobehavioral traits are complex Multifactorial Polygenic Multigenic QTL: quantitative trait locus Region of a chromosome that contains a gene(s) with different alleles that contributes quantitatively to the variance in a trait.
Quantitative Trait Loci (QTL):the specific loci whose allelic differences are responsible for the genetic variation in a quantitative trait (e.g. total sleep time)Note: QTL does not refer to the sum total of all loci that influence a particular trait, only those loci that are functionally polymorphic (with respect to the trait of interest) between the parental strains. Mutagenesis and engineered KOs can artificially alter any gene, however, polymorphisms can represent more subtle “natural” variations.
Cast/EiJ x C57BL/6J
F1 x Cast/EiJ
Backcross progeny have on average:
75% CE, 25% B6 alleles50% C/C, 50% C/B genotypes for all loci
D1Mit119Chr 1, 10 cM
D14Mit169Chr 14, 54 cM
D12Mit141Chr 12, 55 cM
D18Mit122Chr 18, 31 cM
Black = Max likelihood (EM algorithm) Blue = Haley-Knott regression
Generation of C57BL/6J XDBA/2J (BXD-RI) Strains