null vector 中文意思是什麼
null vector
解釋
非退化-
Rlean meat percentage is one of the most important economic traints in pig breeding programs. myostatin is a negative regulator of skeletal muscle growth. null or low activity of myostatin, individual muscle of mutant amimals would show a large and widespread increase in skeletal mass. myostatin null animals have significantly larger diameter or more quantity of fiber skeletal muscle. the phenotype was termed double muscling. in order to probe the relation between myostatin and high lean meat rate and plump - hipped trait, we sythesized the c ' 80 amino acids coding sequence of porcine myostatin and costructed the cloning and expressing vector of it
肌生成抑制素（ myostatin ，即mstn ）是近幾年來（ mcpherrona . c等， 1997 ）發現的骨骼肌生長的負調控因子，它主要在骨骼肌中表達。其活性的喪失，會引起動物肌肉的過度發育，肌纖維直徑變大或肌纖維數增加，表現為雙肌癥狀。肌生成抑制素研究的突破將對豬、肉雞、肉牛等畜禽生產性能的提高具有特別重要的意義。 -
The record header contains a bit vector for indicating null columns
記錄頭包含一個位向量，用來指明空列。
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