Weber J L
Marshfield Medical Research Foundation, Wisconsin 54449.
Genomics. 1990 Aug;7(4):524-30. doi: 10.1016/0888-7543(90)90195-z.
Abundant human interspersed repetitive DNA sequences of the form (dC-dA)n.(dG-dT)n have been shown to exhibit length polymorphisms. Examination of over 100 human (dC-dA)n.(dG-dT)n sequences revealed that the sequences differed from each other both in numbers of repeats and in repeat sequence type. Using a set of precise classification rules, the sequences were divided into three categories: perfect repeat sequences without interruptions in the runs of CA or GT dinucleotides (64% of total), imperfect repeat sequences with one or more interruptions in the run of repeats (25%), and compound repeat sequences with adjacent tandem simple repeats of a different sequence (11%). Informativeness of (dC-dA)n.(dG-dT)n markers in the perfect sequence category was found to increase with increasing average numbers of repeats. PIC values ranged from 0 at about 10 or fewer repeats to above 0.8 for sequences with about 24 or more repeats. (dC-dA)n.(dG-dT)n polymorphisms in the imperfect sequence category showed lower informativeness than expected on the basis of the total numbers of repeats. The longest run of uninterrupted CA or GT repeats was found to be the best predictor of informativeness of (dC-dA)n.(dG-dT)n polymorphisms regardless of the repeat sequence category.
已证明大量形式为(dC-dA)n.(dG-dT)n的人类散布重复DNA序列呈现长度多态性。对100多条人类(dC-dA)n.(dG-dT)n序列的研究表明，这些序列在重复次数和重复序列类型上均彼此不同。使用一套精确的分类规则，这些序列被分为三类：CA或GT二核苷酸连续排列中无中断的完美重复序列（占总数的64%）、重复序列中有一个或多个中断的不完美重复序列（25%）以及具有不同序列的相邻串联简单重复的复合重复序列（11%）。发现完美序列类别中(dC-dA)n.(dG-dT)n标记的信息性随平均重复次数的增加而增加。PIC值范围从重复次数约为10次或更少时的0到重复次数约为24次或更多时的高于0.8。不完美序列类别中的(dC-dA)n.(dG-dT)n多态性显示出的信息性低于基于重复总数预期的信息性。无论重复序列类别如何，发现最长的连续无中断CA或GT重复是(dC-dA)n.(dG-dT)n多态性信息性的最佳预测指标。
