Chen Z Q, Lin C C, Hodgetts R B
Department of Genetics, University of Alberta, Edmonton, Canada.
Genome. 1989 Aug;32(4):646-54. doi: 10.1139/g89-493.
A tandemly repeated DNA sequence possessing a unique PstI site has been characterized in several species of the crane family. The "Pst family" comprises at least 8800 monomer units 187 base pairs (bp) in length and constitutes 0.14% of the genome of the sarus crane (Grus antigone). The array is located in the centromeric heterochromatin of chromosome 2 in the two species where in situ hybridizations of a cloned monomer to metaphase chromosome spreads were carried out. DNA sequence comparisons between five monomer units from G. antigone revealed a high degree of homology between four of the individual repeats, while the fifth was somewhat divergent. The G + C content deduced from the DNA sequence makes it likely that the Pst family constitutes part of a density satellite seen in profiles of crane DNA centrifuged to equilibrium in CsCl. The common occurrence of tandem arrays such as the Pst family, with repeat lengths close to 200 bp, leads us to an hypothesis implicating nucleosomes in the evolution of such families.
一种具有独特PstI位点的串联重复DNA序列已在鹤科的几个物种中得到表征。“Pst家族”至少由8800个长度为187个碱基对（bp）的单体单元组成，占大鸨（Grus antigone）基因组的0.14%。在两个进行了克隆单体与中期染色体铺展原位杂交的物种中，该阵列位于2号染色体的着丝粒异染色质中。对来自大鸨的五个单体单元进行DNA序列比较发现，四个个体重复序列之间具有高度同源性，而第五个则有些差异。从DNA序列推断出的G + C含量表明，Pst家族可能是在CsCl中离心至平衡的鹤DNA图谱中所见密度卫星的一部分。像Pst家族这样重复长度接近200 bp的串联阵列的普遍存在，使我们提出一个假说，即核小体参与了此类家族的进化。
