复制体(clone)

又译克隆。基因上完全相同的细胞或生物体的群体，藉无性方法从单一细胞或生物体得来。复制对大部分生物来说是基本的，因为动植物的体细胞就是单一受精卵有丝分裂最後形成的复制体。较狭义地说，复制体可定义为︰由基因上完全同於母体的单一体细胞长成的生物个体。自古以来复制在园艺业中就很普遍，许多类植物仅靠切下的根、茎、叶的取得和重栽而复制。成年动物和人类的体细胞照例可以在实验室中复制。已可从胚胎细胞成功复制完整的青蛙和老鼠。1996年英国研究人员威尔慕特（Ian Wilmut）率先成功地复制出成年哺乳动物。已从绵羊胚胎造出复制体後，他们有能力用成年绵羊的DNA来造出小羊（桃莉〔Dolly〕，该羊因感染肺疾，已於2003年安乐死）。复制的实际应用在经济上看好，但在哲学上具有争议。

English version：

clone

Population of genetically identical cells or organisms that originated from a single cell or organism by nonsexual methods. Cloning is fundamental to most living things, since the body cells of plants and animals are clones that come ultimately from a single fertilized egg. More narrowly, the term refers to an individual organism grown from a single body cell of its parent that is genetically identical to the parent. Cloning has been commonplace in horticulture since ancient times; many varieties of plants are cloned simply by obtaining cuttings of their leaves, stems, or roots and replanting them. The body cells of adult humans and other animals are routinely cultured as clones in the laboratory. Entire frogs and mice have been successfully cloned from embryonic cells. British researchers led by Ian Wilmut achieved the first success in cloning an adult mammal in 1996. Having already produced clones from sheep embryos, they were able to produce a lamb (Dolly) using DNA from an adult sheep. The practical applications of cloning are economically promising but philosophically unsettling.