Fig. 5.

QTL mapping of high acetic acid tolerance using individual F7 segregants. a For each of the individual F7 segregants, the parent-of-origin linkage information was determined by using a distance-based method followed by the segmentation of individual chromosomes. Genomic regions linked either to the genome of the superior parent (>0; green) or to that of the inferior parent (<0; red) were derived by averaging the parent-of-origin linkage information for the nine most tolerant segregants of the F7 pool. Horizontal lines are included to mark the threshold values of ±0.7 used for QTL identification (see “Methods” for details). b Detailed view of the identified QTL regions when different numbers of F7 strains (the 9, 18, or 27 strains with highest acetic acid tolerance) are considered. Inclusion of additional strains with less extreme acetic acid tolerance results in QTL regions becoming either less pronounced (QTL1, QTL3, QTL5), emerge when less tolerant strains are considered (QTL4), or are present when only the most tolerant strains are included in the analysis (QTL6)