Mol Biol Evol. 2012 Jan;29(1):7-11. doi: 10.1093/molbev/msr173. Epub 2011 Jun 28.
Concerted evolution leading to homogenization of tandemly repeated DNA arrays is widespread and important for genome evolution. We investigated the range and nature of the process at chromosomal and array levels using the 1.688 tandem repeats of Drosophila melanogaster where large arrays are present in the heterochromatin of chromosomes 2, 3, and X, and short arrays are found in the euchromatin of the same chromosomes. Analysis of 326 euchromatic and heterochromatic repeats from 52 arrays showed that the homogenization of 1.688 repeats occurred differentially for distinct genomic regions, from euchromatin to heterochromatin and from local arrays to chromosomes. We further found that most euchromatic arrays are either close to, or are within introns of, genes. The short size of euchromatic arrays (one to five repeats) could be selectively constrained by their role as gene regulators, a situation similar to the so-called "tuning knobs."
协同进化导致串联重复 DNA 阵列的同质化现象广泛存在，对基因组进化具有重要意义。我们在染色体和阵列水平上研究了这一过程的范围和性质，使用的是果蝇 1.688 串联重复序列，其中大的阵列存在于染色体 2、3 和 X 的异染色质中，而短的阵列存在于相同染色体的常染色质中。对来自 52 个阵列的 326 个常染色质和异染色质重复序列的分析表明，1.688 重复序列的同质化在不同的基因组区域发生了不同的变化，从常染色质到异染色质，从局部阵列到染色体。我们进一步发现，大多数常染色质阵列要么靠近基因，要么位于基因的内含子中。常染色质阵列的短尺寸（一到五个重复）可能因其作为基因调节剂的作用而受到选择性限制，这种情况类似于所谓的“调谐旋钮”。
