Assum G, Fink T, Klett C, Lengl B, Schanbacher M, Uhl S, Wöhr G
Abteilung Humangenetik Universität, Ulm, Federal Republic of Germany.
Genomics. 1991 Oct;11(2):397-409. doi: 10.1016/0888-7543(91)90148-8.
By hybridizing total human DNA with probes derived from the extrachromosomal circular DNA fraction of cultured cells, we detected a human multisequence family, called chAB4, previously unknown. Approximately 50 copies of this sequence are located in the haploid human genome. The repetition units of chAB4 are 35 kb long and the units are tandemly arranged. DNA sequence analysis of parts of the chAB4 unit revealed no direct evidence for a possible function of the family, but possibly chAB4 harbors a gene. Family members are located on human chromosomes 1, 3, and 9 and on the short arms of chromosomes 13-15, 21, and 22. Therefore, in addition to the rDNA, chAB4 is the second class of clustered repetitive sequences with a relatively long repetition unit localized on the short arms of all acrocentric chromosomes. Some evolutionary aspects arising from the structure of chAB4, the established parts of its DNA sequences, and the chromosomal localization of this new multisequence family are discussed.
通过将人类总DNA与源自培养细胞的染色体外环状DNA片段的探针杂交，我们检测到了一个此前未知的人类多序列家族，称为chAB4。该序列在单倍体人类基因组中约有50个拷贝。chAB4的重复单元长35 kb，且这些单元串联排列。对chAB4单元部分进行的DNA序列分析未发现该家族可能具有某种功能的直接证据，但chAB4可能含有一个基因。家族成员位于人类1号、3号和9号染色体以及13 - 15号、21号和22号染色体的短臂上。因此，除了核糖体DNA（rDNA）之外，chAB4是第二类成簇重复序列，其具有相对较长的重复单元，定位于所有近端着丝粒染色体的短臂上。本文讨论了由chAB4的结构、其DNA序列的已知部分以及这个新的多序列家族的染色体定位所引发的一些进化方面的问题。
