Data from: Healing quantitative trait loci in a combined cross analysis using related mouse strain crosses

Inbred mouse strains MRL and LG share the ability to fully heal ear hole punches with the full range of appropriate tissues without scarring. They also share a common ancestry, MRL being formed from a multi-strain cross with two final backcrosses to LG before being inbred by brother-sister mating. Many gene mapping studies for healing ability have been performed using these two strains, resulting in the location of about 20 quantitative trait loci (QTLs). Here, we combine two of these crosses (N = 638), MRL/lpr x C57BL/6NTac and LG/J x SM/J, in a single combined cross analysis to increase mapping power, decrease QTL support intervals, separate multiple QTLs, and establish allelic states at individual QTL. The combined cross analysis located 11 QTLs, 6 affecting only one cross (5 LG x SM and 1 MRL x B6) and 5 affecting both crosses, approximately the number of common QTLs expected given strain SNP similarity. Amongst the 5 QTLs mapped in both crosses, three had significantly different genetic effects, additive in one cross and over- or under-dominant in the other. It is possible that allelic states at these three loci are different in SM and B6 because they lead to differences in dominance interactions with the LG and MRL alleles. QTL support intervals are 40% smaller in the combined cross analysis than in either of the single crosses. Combined cross analysis was successful in enhancing the interpretation of earlier QTL results for these strains.

近交系小鼠品系MRL与LG均可完整修复耳部穿孔创伤，再生全套正常组织且无瘢痕形成。二者拥有共同的遗传起源：MRL品系由多品系杂交培育，在通过兄妹交配进行近交固定前，曾两次回交于LG品系。针对该创伤愈合能力的基因定位研究已基于这两个品系广泛开展，迄今已定位约20个数量性状位点（quantitative trait loci，QTL）。
本研究将两项杂交群体（样本量N=638）——MRL/lpr × C57BL/6NTac与LG/J × SM/J——合并开展联合连锁分析，以期提升定位效力、缩小QTL置信区间、区分多个连锁的QTL，并明确单个QTL的等位基因状态。联合分析共定位到11个QTL：其中6个仅在单一杂交组合中检测到遗传效应（5个来自LG×SM杂交组合，1个来自MRL×B6杂交组合），剩余5个在两个杂交组合中均检测到效应，该数量与基于品系单核苷酸多态性（single nucleotide polymorphism，SNP）相似性预期的共有QTL数量基本一致。
在两个群体中均定位到的5个QTL中，3个的遗传效应存在显著差异：在一个群体中呈加性效应，在另一群体中则表现为超显性或亚显性。推测SM与B6品系在这3个位点的等位基因状态存在差异，该差异可能导致其与LG及MRL等位基因间的显性互作模式发生改变。联合分析得到的QTL置信区间较任一单一杂交组合分析缩小了约40%。本联合分析成功优化了前期针对这两个品系的QTL研究结果的阐释效果。