PCK1基因下游82.4kb处的选择信号可能导致其在鸭驯化过程中的表达变化  

Selection Signals 82.4 kb Downstream from PCK1 Might Induce Differential Expression of PCK1 During Duck(Anas platyrhynchos domesticus) Domestication

作　　者：陈黎[1] 刘睿[2] 李国勤[1] 沈军达[1] 卢立志[1] 

机构地区：[1]浙江省农业科学院畜牧兽医研究所,杭州310021 [2]中国农业大学生物学院,北京100193

出　　处：《农业生物技术学报》2016年第6期881-888,共8页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金项目(No.31402065);国家"十二五"科技支撑计划项目(No.2012BAD39B00);国家水禽产业技术体系专项(CARS-43-2)

摘　　要：磷酸烯醇式丙酮酸羧激酶基因（phosphoenolpyruvate carboxykinase 1（Soluble）,PCK1）是糖异生及甘油异生的关键基因。为分析PCK1基因在家鸭（Anas platyrhynchos domesticus）驯化过程中是否出现表达差异以及是否受到驯化选择,本研究分别以绿头野鸭（Anas platyrhynchos）、绍兴鸭及北京鸭作为野生品种、蛋鸭及肉鸭品种代表,检测PCK1基因在这3个品种中的表达水平、杂合度（Hp）以及遗传距离（Fst）。表达分析发现,与绿头野鸭相比,PCK1在绍兴鸭及北京鸭肝脏组织中表达量分别下降了3倍、10倍;在脂肪组织中分别下降了3倍、26倍。根据全基因组Z（Hp）及Z（Fst）分布情况,以Z（Hp）〈-3、Z（Fst）〉2作为选择信号筛选标准。按照此标准发现PCK1基因下游82.4 kb处（KB742479.1：2 220 079-2 259 967 bp）出现选择信号。与绿头野鸭相比,该区域在绍兴鸭及北京鸭中杂合度均降低,Z（Hp）值分别为-3.92及-3.63;遗传距离均最大,Z（Fst）值分别为3.91及2.54。对该区域临近基因（ENSAPLG00000002901,C20orf85,PCK1）的表达分析发现,仅PCK1基因在鸭驯化过程中出现表达差异。因此,推测该选择信号可能导致了PCK1基因在家鸭与野鸭间的表达差异。本研究首次较深入的探索了鸭的驯化遗传机制;研究发现鸭驯化过程中PCK1存在表达变化,同时其下游82.4 kb处出现选择信号,这些结果为进一步研究PCK1的功能提供了线索。Phosphoenolpyruvate carboxykinase 1 （Soluble） （PCK1） encodes the rate-limiting enzyme （phosphoenolpyruvate carboxykinase, cytosolic,PEPCK-C） in gluconeogenesis, and is the key gene at controlling the overall level of glucose. Several studies have reported that PCK1 had experienced selective adaption to environment changes. In this research, in order to study the expression differentiation of PCK1 during duck （Anas platyrhynchos domesticus） domestication, and analyze whether it had signature of selection adapted to the domestication, mallard （Anas platyrhynchos）, Shaoxing ducks and Peking ducks were chosen as the representative of the wild breed, egg-type and meat-type ducks, respectively. Expression analysis found that PCK1 was down regulated in the 2 domesticated breeds. In comparison to the mallard, PCK1 was down-regulated 3- and 10- folds in the liver of Shaoxing ducks and Peking ducks, respectively and down-regulated 3- and 26- folds in the abdominal fat of Shaoxing ducks and Peking ducks, respectively. To identify whether PCK1 was selected during duck domestication, we performed whole-genome resequencing of mallards （n=27）, Shaoxing ducks （n=27） and Peking ducks （n=27）, and 12179415 SNP were obtained for genome wide analysis of selection signals, including analysis of the heterozygosity （Hp） and genetic distance （Fst）. Z transformed whole-genome Hp （Z（Hp）） and Fst （Z（Fst）） distribution showed that Z（Hp）〈 -3 and Z（Fst）〉2 represented the extreme end of the distribution, and thus were described as the threshold of putatively selected signals. In this study, we only focus on selection signals in scaffold KB742479.1 which containing PCK1. And to reduce the interference of fixation due to genetic drift within populations, we combined results from Shaoxing ducks and Peking ducks and only chosen regions with reduced heterozygosity and increased genetic distance in both of the 2 breeds relative to Anas platyrhynchos. By using these thresholds KB74247

关 键 词：PCK1基因 杂合度 遗传距离 

分 类 号：Q31[生物学—遗传学]