Chaudhari N, Craig S P
Biochim Biophys Acta. 1979 May 24;562(3):438-52. doi: 10.1016/0005-2787(79)90107-2.
The rates of evolution of purified long and short repetitive DNA sequences were examined by hybridisation analysis between the DNAs from several species of sea urchins. We find that the rates of nucleotide substitution are very comparable within mutually retained sequences for the two classes of repetitive DNA. The loss of hybridisable sequences between species also occurs at similar rates among both the short and long repetitive DNA sequences. Between species that separated less than 50 million years ago, hybridisable short repetitive sequences are lost all through the spectrum of reiteration frequencies. The long repeats contain a few sequences which are highly conserved within all of the species examined, and which amount to approximately 1% of the total genome. The short repetitive class, on the other hand, does not seem to contain any such highly conserved elements. The long repetitive sequences internally appear to contain short 'units' of reiteration, which may comprise families within the long repetitive class. We find no evidence to indicate that the majority of long and short repetitive sequences evolve by different mechanisms or at different rates.
通过对几种海胆的DNA进行杂交分析，研究了纯化的长重复DNA序列和短重复DNA序列的进化速率。我们发现，对于这两类重复DNA，在相互保留的序列中核苷酸替换率非常相近。物种间可杂交序列的丢失在短重复DNA序列和长重复DNA序列中也以相似的速率发生。在分离时间不到5000万年的物种之间，可杂交的短重复序列在整个重复频率范围内都会丢失。长重复序列包含一些在所研究的所有物种中高度保守的序列，约占基因组总量的1%。另一方面，短重复序列类似乎不包含任何此类高度保守的元件。长重复序列内部似乎包含短的重复“单元”，这可能构成长重复序列类中的家族。我们没有发现证据表明大多数长重复序列和短重复序列通过不同的机制或以不同的速率进化。
