Division of Evolutionary Biology, Ludwig-Maximilians-Universität (LMU) München, 82152 Planegg-Martinsried, Germany and.
Centre for Functional Genomics, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, United Kingdom.
G3 (Bethesda). 2019 Nov 5;9(11):3715-3725. doi: 10.1534/g3.119.400453.
Ectothermic species such as insects are particularly vulnerable to climatic fluctuations. Nevertheless, many insects that evolved and diversified in the tropics have successfully colonized temperate regions all over the globe. To shed light on the genetic basis of cold tolerance in such species, we conducted a quantitative trait locus (QTL) mapping experiment for chill coma recovery time (CCRT) in , a cosmopolitan species that has expanded its range from tropical to temperate regions. We created a mapping population of recombinant inbred advanced intercross lines (RIAILs) from two founder strains with diverging CCRT phenotypes. The RIAILs were phenotyped for their CCRT and, together with the founder strains, genotyped for polymorphic markers with double-digest restriction site-associated DNA (ddRAD) sequencing. Using a hierarchical mapping approach that combined standard interval mapping and a multiple-QTL model, we mapped three QTL which altogether explained 64% of the phenotypic variance. For two of the identified QTL, we found evidence of epistasis. To narrow down the list of cold tolerance candidate genes, we cross-referenced the QTL intervals with genes that we previously identified as differentially expressed in response to cold in , and with thermotolerance candidate genes of Among the 58 differentially expressed genes that were contained within the QTL, showed a significant interaction of the CCRT phenotype and gene expression. Further, we identified the orthologs of four thermotolerance candidate genes, , , (/) and (/) as candidates for cold tolerance in .
变温动物（如昆虫）特别容易受到气候波动的影响。然而，许多在热带地区进化和多样化的昆虫已经成功地在全球温带地区定居。为了揭示这些物种耐寒性的遗传基础，我们对一个世界性物种 进行了数量性状位点（QTL）映射实验，该物种的耐寒性表型已经从热带扩展到温带。我们从具有不同 CCRT 表型的两个起始菌株中创建了一个重组近交系高级互交系（RIAIL）的作图群体。对 RIAIL 进行 CCRT 表型分析，并与起始菌株一起，对具有双酶切限制位点相关 DNA（ddRAD）测序的多态性标记进行基因型分析。使用组合标准区间作图和多 QTL 模型的层次作图方法，我们共鉴定到三个 QTL，共解释了 64%的表型方差。对于两个鉴定到的 QTL，我们发现存在上位性的证据。为了缩小耐寒候选基因的列表，我们将 QTL 区间与我们之前在 中鉴定到的冷响应差异表达基因，以及 中的耐热候选基因进行交叉参考。在包含在 QTL 内的 58 个差异表达基因中， 与 CCRT 表型和基因表达之间存在显著的互作。此外，我们鉴定到四个 耐热候选基因的同源基因， 、 、 （/）和 （/）作为 在 中耐寒性的候选基因。
