Contrasting patterns of expression divergence in early and late stages of population divergence in mice

We compared gene expression differences in the polytypic species complex Mus musculus (Mus musculus musculus, Mus musculus domesticus, Mus musculus castaneus and Mus musculus ssp) with that of Mus spretus via oligonucleotide microarrays representing more than 20,000 genes. Analysis of the results by two way ANOVA statistics suggests that the most genes with significant differences in expression levels among the subspecies are found in liver and kidney and the least in testis. This picture is different when one compares with Mus spretus, where the largest number of differences is found in testis. Keywords: multi-species comparison The design we employed is a reference design. All tissues were hybridized against a pool of that same tissue from 9 C57BL6 mice. All mice were roughly 12 weeks of age. To control for biological variation, we have used several individual males from each sub-species. RNA was isolated from three different organs, namely brain, liver/kidney and testis.本研究借助覆盖超过20000个基因的寡核苷酸微阵列（oligonucleotide microarray），对多型物种复合群小家鼠（Mus musculus）及其四个亚种——小家鼠指名亚种（Mus musculus musculus）、小家鼠欧洲亚种（Mus musculus domesticus）、小家鼠亚洲亚种（Mus musculus castaneus）以及小家鼠未定亚种（Mus musculus ssp）——与西氏小家鼠（Mus spretus）之间的基因表达差异展开了比较分析。通过双因素方差分析（two-way ANOVA）对实验结果进行统计分析后发现，亚种间表达水平存在显著差异的基因在肝脏与肾脏中数量最多，在睾丸中最少。但当与西氏小家鼠进行对照比较时，这一分布模式发生了改变——其亚种间表达差异最为显著的组织为睾丸。关键词：多物种比较分析。本研究采用的实验设计为参考设计（reference design），所有组织样本均与来自9只C57BL/6小鼠的同组织混合样本进行杂交。所有实验小鼠的周龄均约为12周，为控制生物学变异，本研究从每个亚种中选取了多只雄性个体作为实验材料。本研究从脑、肝/肾以及睾丸三种不同组织中分离得到了RNA。