Klein W H, Thomas T L, Lai C, Scheller R H, Britten R J, Davidson E H
Cell. 1978 Aug;14(4):889-900. doi: 10.1016/0092-8674(78)90344-6.
Cloned repetitive sequences from the S. purpuratus genome a few hundred to approximately 1000 nucleotides long were used to investigate the characteristics of individual repetitive sequence families. They wer terminally labeled by the kinase procedure and reacted with sheared S. purpuratus DNA. Repetition frequencies were measured for 26 individual families and were found to vary from a few to several thousand copies per genome. Estimates of sequence divergence were made for 18 cloned repeat families by measuring thermal stability of the heteroduplexes formed between the genomic DNA and the cloned fragments, compared with that of the renatured cloned fragments. The difference was less than 4 degrees C for three of the 18 families, and less than 10 degress C for 13 of the 18 families. These 13 repetitive sequence families lack any detectable highly divergent sequence relatives, and the results reported are shown not to change when the renaturation criterion is lowered below 55 degrees C in 0.18 M Na+. Five of the 18 cloned families displayed greater sequence divergence. The average sequence divergence of the total short repetitive sequence fraction of S. purpuratus DNA was found to match closely the average of the divergences of the cloned repeat sequences.
从紫球海胆基因组中克隆出的长度为几百至约1000个核苷酸的重复序列，用于研究各个重复序列家族的特征。它们通过激酶法进行末端标记，并与经剪切的紫球海胆DNA反应。测定了26个个体家族的重复频率，发现每个基因组中的重复频率从几个到几千个拷贝不等。通过测量基因组DNA与克隆片段之间形成的异源双链体的热稳定性，并与复性后的克隆片段进行比较，对18个克隆的重复家族进行了序列差异估计。18个家族中有3个家族的差异小于4℃，18个家族中有13个家族的差异小于10℃。这13个重复序列家族缺乏任何可检测到的高度分化的序列亲属，并且当复性标准在0.18M Na+中降低到55℃以下时，所报道的结果不变。18个克隆家族中有5个显示出更大的序列差异。发现紫球海胆DNA的总短重复序列部分的平均序列差异与克隆重复序列差异的平均值密切匹配。
