摘要
African bovine trypanosomiasis caused by Trypanosoma sp., is a major constraint on cattle productivity in sub-Saharan Africa. Some African Bos taurus breeds are highly tolerant of infection, but the potentially more productive Bos indicus zebu breeds are much more susceptible. Zebu cattle are well adapted for plowing and haulage, and increasing their tolerance of trypanosomiasis could have a major impact on crop cultivation as well as dairy and beef production. We used three strategies to obtain short lists of candidate genes within QTL that were previously shown to regulate response to infection. We analyzed the transcriptomes of trypanotolerant N'Dama and susceptible Boran cattle after infection with Trypanosoma congolense. We sequenced EST libraries from these two breeds to identify polymorphisms that might underlie previously identified quantitative trait loci (QTL), and we assessed QTL regions and candidate loci for evidence of selective sweeps. The scan of the EST sequences identified a previously undescribed polymorphism in ARHGAP15 in the Bta2 trypanotolerance QTL. The polymorphism affects gene function in vitro and could contribute to the observed differences in expression of the MAPK pathway in vivo. The expression data showed that TLR and MAPK pathways responded to infection, and the former contained TICAM1, which is within a QTL on Bta7. Genetic analyses showed that selective sweeps had occurred at TICAM1 and ARHGAP15 loci in African taurine cattle, making them strong candidates for the genes underlying the QTL. Candidate QTL genes were identified in other QTL by their expression profile and the pathways in which they participate.
摘要译文
造成锥虫属非洲锥虫病的牛是在撒哈拉以南非洲AfricaSome普通牛品种的包容度很高的感染牛生产力的主要制约因素，但潜在的生产力瘤牛瘤牛的品种更为susceptibleZebu牛很好地适应耕作和运输，并提高其锥虫病的耐受性可能对作物种植产生了重大影响，以及奶制品和牛肉生产我们用三招获得先前证明是调节对感染的反应中QTL候选基因的短名单我们分析锥虫N''''Dama和易感勃然牛的转录感染锥虫congolense后我们测序这两个品种的EST库，以确定可能背后先前确定的数量性状位点（QTL）多态性，我们评估的QTL区域和候选基因进行选择性的扫描证据该EST序列扫描在Bta2 trypanotolerance QTL确定了先前未描述多态性ARHGAP15多态性影响基因功能的体外和可在体内MAPK通路的表达向观察到的差异表达数据表明TLR和MAPK途径响应感染，而前者所含TICAM1，这是Bta7的QTL内遗传分析表明，选择性的扫描已经在非洲牛磺酸牛TICAM1和ARHGAP15基因位点发生，使他们的基本QTL的基因强有力的候选人候选基因QTL被他们的表达谱在其他QTL识别和途径其所参与
Harry Noyes[a];[1]; Andy Brass[b];[1]; Isaiah Obara[c]; Susan Anderson[d]; Alan L. Archibald[d]; Dan G. Bradley[e]; Paul Fisher[b]; Abigail Freeman[e]; John Gibson[c];[2]; Michael Gicheru[f]; Laurence Hall[d]; Olivier Hanotte[c];[3]; Helen Hulme[b]; Declan McKeever[g]; Caitriona Murray[e]; Sung Jung Oh[h]; Catriona Tate[a];[b]; Ken Smith[g]; Miika Tapio[c];[4]; John Wambugu[b]; Diana J. Williams[i]; Morris Agaba[c]; and Stephen J. Kemp[a];[c];[5]. Genetic and expression analysis of cattle identifies candidate genes in pathways responding to Trypanosoma congolense infection[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2011,108(22): 9304-9309