Alexandrov I A, Mitkevich S P, Yurov Y B
All Union Research Center of Mental Health, Academy of Medical Sciences of USSR, Moscow.
Chromosoma. 1988;96(6):443-53. doi: 10.1007/BF00303039.
The chromosomal distribution of sequences homologous to 18 coned alpha satellite fragments was established by in situ hybridization. It appeared that all the cloned sequences were members of small repeated families located on single chromosome pairs. Among the sequences studied specific molecular markers for chromosomes 3, 4, 10, 11, 17, 18 and X were found. Comparison of the hybridization spectra obtained under non-stringent conditions and of restriction site periodicities in different chromosome-specific families allowed the identification of three "suprachromosomal" families, each located on a characteristic set of chromosomes. The three families together cover all the autosomes and the X chromosome. These data plus those reported previously allow part of the phylogenetic tree of chromosome-specific alpha satellite repeats to be drawn. Each suprachromosomal family has presumably originated from a distinct ancestral sequence and consists of certain types of monomers. Ancestral sequences have evolved into a number of chromosome-specific families by cycles of interchromosomal transfers and subsequent amplification events. The high homogeneity of chromosome-specific families may be a result of intrachromosomal homogenization of amplification units in chromosome-specific alpha satellite domains.
通过原位杂交确定了与18个克隆的α卫星片段同源的序列的染色体分布。结果显示，所有克隆序列都是位于单个染色体对上的小重复家族的成员。在所研究的序列中，发现了3号、4号、10号、11号、17号、18号染色体和X染色体的特异性分子标记。比较在非严格条件下获得的杂交图谱以及不同染色体特异性家族中的限制性酶切位点周期性，鉴定出三个“超染色体”家族，每个家族位于一组特定的染色体上。这三个家族共同覆盖了所有常染色体和X染色体。这些数据加上先前报道的数据，使得能够绘制出部分染色体特异性α卫星重复序列的系统发育树。每个超染色体家族大概起源于一个独特的祖先序列，由某些类型的单体组成。祖先序列通过染色体间转移和随后的扩增事件循环演变成许多染色体特异性家族。染色体特异性家族的高度同质性可能是染色体特异性α卫星结构域中扩增单元的染色体内同质化的结果。
