Biomaterial Database

Satellite Ic: a possible link between the satellite DNAs of D. virilis and D. melanogaster. 1979

J I Mullins, and M Blumenfeld

In this study, we isolated and characterized a previously undetected cryptic satellite DNA comprising 0.1% of the total nuclear genome of D. virilis. This satellite is hidden from detection in neutral CsCl by satellite I and is therefore designated cryptic satellite I or Ic. Sequence analysis reveals that Ic is the repeating heptanucleotide [poly d(AATATAG): d(CTATATT)]. It is more closely related to the three simple sequence satellite DNAs of D. melanogaster, a distantly related species, than it is to any of the major D. virilis satellite DNA sequences. Ic may therefore be a link between the simple sequence satellites of D. virilis and D. melanogaster. As an extension of this theory, we have constructed a "family tree" linking the satellites of D. virilis and D. melanogaster by a series of "simple" operations. Only one intermediate required by this evolutionary scheme has not yet been identified.

UI	MeSH Term	Description	Entries
D004276	DNA, Satellite	Highly repetitive DNA sequences found in HETEROCHROMATIN, mainly near centromeres. They are composed of simple sequences (very short) (see MINISATELLITE REPEATS) repeated in tandem many times to form large blocks of sequence. Additionally, following the accumulation of mutations, these blocks of repeats have been repeated in tandem themselves. The degree of repetition is on the order of 1000 to 10 million at each locus. Loci are few, usually one or two per chromosome. They were called satellites since in density gradients, they often sediment as distinct, satellite bands separate from the bulk of genomic DNA owing to a distinct BASE COMPOSITION.	Satellite DNA,Satellite I DNA,DNA, Satellite I,DNAs, Satellite,DNAs, Satellite I,I DNA, Satellite,I DNAs, Satellite,Satellite DNAs,Satellite I DNAs
D004330	Drosophila	A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.	Fruit Fly, Drosophila,Drosophila Fruit Flies,Drosophila Fruit Fly,Drosophilas,Flies, Drosophila Fruit,Fly, Drosophila Fruit,Fruit Flies, Drosophila
D004331	Drosophila melanogaster	A species of fruit fly frequently used in genetics because of the large size of its chromosomes.	D. melanogaster,Drosophila melanogasters,melanogaster, Drosophila
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species