期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：7
页码：4490-4494
DOI：10.1073/pnas.78.7.4490
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A highly repeated DNA sequence has been isolated from the maize genome as a satellite in actinomycin D/CsCl gradients. By using maize stocks differing in their heterochromatin content we have established that the sequence is a major constituent of one class of heterochromatin, knob heterochromatin, which can occur at 23 locations in the chromosome complement. The repeating unit, of 185 base pairs, has been cloned in plasmid pBR322 and its nucleotide sequence has been determined. The presence of this DNA sequence in knob heterochromatin and its absence from centromeric, nucleolar, and B chromosome heterochromatin parallels the cytogenetic differentiation previously described for these classes of heterochromatin in maize. Because knob heterochromatin has a distinctive cytological appearance and is unique in showing neocentric activity at meiosis, its association with a particular repeated DNA sequence may reflect a functional role for the sequence in the cell cycle.
关键词：satellite DNA ; cloning ; in situ hybridization
