分子生物学的主要兴趣之一是探索各阶段基因活性的调节机理.自从Jacob与Monod提出操纵子模型(1961)以后,对特定基因的顺位及对位调节机理已经有人作过研究.在较高级的真核细胞中,普遍存在着二倍体,因此有可能发生像基因剂量与双等位基因相互作用这样更进一步的调节方式.在对癌基因的研究中,有几个对位调节的例子引起了人们的兴趣. One of the major interests of molecular biology is to explore the regulatory mechanisms of gene activity at each stage. Since the operon model proposed by Jacob and Monod (1961), the mechanism of the regulation of the position and alignment of specific genes has been studied. In advanced eukaryotic cells, diploids are ubiquitous, so there may be a further mode of regulation like gene dose and biallelic interactions. In the study of oncogenes, there are several alignments The example has caused people’s interest.