Chromosome-specific alpha satellites: two distinct families on human chromosome 18.

Two types of human chromosome 18-specific alpha satellite fragments have been cloned and sequenced. They represent closely related but distinct alphoid families formed by two different types of the higher-order repeated units (1360-bp EcoRI and 1700-bp HindIII fragments) that do not alternate in the genome. The individual repeats within each family are 99% identical and interfamily homology is about 78%. Sequence analysis shows that both repeats belong to alphoid suprachromosomal family 2, but their homology is not higher than that of family members located on different chromosomes. Therefore, the two repeats shared a common origin in the recent past, although they are not the direct offspring of one ancestral sequence. Our data indicate that these two 18-specific domains have appeared as a result of two separate amplification events. Despite the high degree of homology, they are not undergoing intrachromosomal homogenization, although some variation of this process might take place within each domain.

[1]  H. Willard,et al.  Nucleotide sequence heterogeneity of alpha satellite repetitive DNA: a survey of alphoid sequences from different human chromosomes. , 1987, Nucleic acids research.

[2]  L. Manuelidis,et al.  Homology between human and simian repeated DNA , 1978, Nature.

[3]  Aleksandrova Ia,et al.  [Cloned fragment of human alphoid DNA--a molecular marker of the pericentromeric region of chromosome 18]. , 1986 .

[4]  Aleksandrova Ia,et al.  Chromosome organization of human alphoid DNA , 1986 .

[5]  B. Vissel,et al.  Identification of two distinct subfamilies of alpha satellite DNA that are highly specific for human chromosome 15. , 1990, Genomics.

[6]  Huntington F. Willard,et al.  Hierarchical order in chromosome-specific human alpha satellite DNA , 1987 .

[7]  B. Calabretta,et al.  Recent amplification of an alpha satellite DNA in humans. , 1985, Nucleic acids research.

[8]  D. Gillespie,et al.  Definition of a second dimeric subfamily of human α satellite DNA , 1989 .

[9]  H. Willard,et al.  Patterns of intra- and interarray sequence variation in alpha satellite from the human X chromosome: evidence for short-range homogenization of tandemly repeated DNA sequences. , 1989, Genomics.

[10]  C. Bostock,et al.  Homologous subfamilies of human alphoid repetitive DNA on different nucleolus organizing chromosomes. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[11]  H. Willard,et al.  Chromosome-specific alpha satellite DNA: nucleotide sequence analysis of the 2.0 kilobasepair repeat from the human X chromosome. , 1985, Nucleic acids research.

[12]  P. Devilee,et al.  Sequence heterogeneity within the human alphoid repetitive DNA family. , 1986, Nucleic acids research.

[13]  H. Ropers,et al.  Isolation and characterization of alphoid DNA sequences specific for the pericentric regions of chromosomes 4, 5, 9, and 19. , 1988, Cytogenetics and cell genetics.

[14]  W. Gilbert,et al.  Sequencing end-labeled DNA with base-specific chemical cleavages. , 1980, Methods in enzymology.

[15]  H. Willard,et al.  Genomic organization of alpha satellite DNA on human chromosome 7: evidence for two distinct alphoid domains on a single chromosome , 1987, Molecular and cellular biology.