Buroker N E, Brown J R, Gilbert T A, O'Hara P J, Beckenbach A T, Thomas W K, Smith M J
School of Medicine, Department of Pediatrics, University of Washington, Seattle 98195.
Genetics. 1990 Jan;124(1):157-63. doi: 10.1093/genetics/124.1.157.
Extensive length polymorphism and heteroplasmy (multiple forms within an individual) of the D-loop region are observed in mitochondrial DNA of the white sturgeon (Acipenser transmontanus). The nucleotide sequence of this region, for both a short and a long form, shows that the differences are due to variable numbers of a perfect 82-bp direct repeat. We propose a model for the replicative origin of length differences, involving a competitive equilibrium between the heavy strand and the D-loop strand. This model suggests that frequent misalignment in the repeat region prior to elongation, facilitated by a stable secondary structure in the displaced strand, can explain both the polymorphism and heteroplasmy in this species.
在白鲟（Acipenser transmontanus）的线粒体DNA中观察到D环区域存在广泛的长度多态性和异质性（个体内的多种形式）。该区域短形式和长形式的核苷酸序列表明，差异是由于一个完美的82bp直接重复序列的数量可变。我们提出了一个长度差异复制起源的模型，涉及重链和D环链之间的竞争平衡。该模型表明，在延伸之前重复区域中频繁的错配，由置换链中的稳定二级结构促进，可以解释该物种中的多态性和异质性。
