Talk:Satellite DNA

Molecular Biology: Genetics / MCB Mid‑importance

	This article is within the scope of WikiProject Molecular Biology, a collaborative effort to improve the coverage of Molecular Biology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Molecular BiologyWikipedia:WikiProject Molecular BiologyTemplate:WikiProject Molecular BiologyMolecular Biology articles
Mid	This article has been rated as Mid-importance on the importance scale.
	This article is supported by the Genetics task force (assessed as Mid-importance).
	This article is supported by the Molecular and Cell Biology task force (assessed as Mid-importance).
	An editor has requested that an image or photograph be added to this article.

Untitled[edit]

Why do we call the repetitive DNA as "Satellite DNA"?

The term "satellite DNA" was coined because repetitive sequences tend to have base compositions that are different from ordinary DNA sequences, thus having different densities when subjected to buoyant density centrifugation. Sequences rich in G and C have higher density than ordinary DNA while sequences rich in A and T tend to have lower density. When subjected to buoyant density centrifugation the repetitive sequences float above or below the bulk of the DNA and graphs show peaks that separate from the ordinary DNA sequences. This term arose in the early 1960's and was influenced by the new phenomenon of man-made satellites orbiting the Earth, with the smaller satellite DNA peaks forming analogous entities on either side of the larger bulk DNA peak. There are also "cryptic satellite DNAs" with repetitive sequences that are not significantly biased in base composition and therefore are hidden because they have buoyant densities similar to the bulk of ordinary DNA sequences. (See publications from the lab of D.M. Skinner). Richard F. Fowler, 4/24/2016 — Preceding unsigned comment added by Richard.F.Fowler (talk • contribs) 11:36, 25 April 2016 (UTC)[reply]

If I recall correctly, it's for historical reasons. In the early days, when they did differential centrifugation of DNA it got separated in a different layer from the rest. Hence, satellite DNA. — Preceding unsigned comment added by 157.92.4.72 (talk) 18:02, 1 March 2013 (UTC)[reply]

What does "Satellite" mean exactly in this?

I never thought about microsatellites as repeat sequences. they're usually in the untranscribed section of dna, short (2-10bp) and serve as markers. ribosome slippage in huntington's disease, for example, isn't a microsatellite as far as i know, i thought it was a STR. —Preceding unsigned comment added by Mkayatta (talk • contribs) 14:21, 2 November 2007 (UTC)[reply]

Wikipedia talk:Articles for creation/Three Dimensional Structures in Satellite DNA[edit]

Please consider incorporating any useful material from the above submission into this article. The submission is eligible for deletion in 6 months. ~Kvng (talk) 20:33, 22 April 2015 (UTC)[reply]

Structure (Old References)[edit]

I'm placing the following here for reference because I'm cleaning up the references. I believe this information is identical (or nearly so) to the proposed deleted article linked above. Lakster37 (talk) 17:39, 7 July 2015 (UTC)[reply]

Satellite DNA adopts higher-order three-dimensional structures in eukaryotic organisms. This was demonstrated in the land crab Gecarcinus lateralis, who's DNA contains 3% of a GC-rich sequence consisting of tandem repeats of a ~2100 base pair (bp) repeating unit, called RU (7,8,9). The RU is arranged in long tandem arrays with approximately 16,000 copies per genome. Several RU sequences were cloned and sequenced to reveal conserved regions of conventional DNA sequences interspersed with microsatellite repeats, in addition to long runs (20-25 bp) of G and C bases pairs with G on one strand and C on the other (3,4,5). The microsatellite repeats were also biased in strand composition in the microsatellite regions with pyrimidines (C,T) on one strand and purines (A,G) on the other. The most prevalent repeated sequences in the embedded microsatellite regions were CCT/AGG and CCCT/AGGG (3,4,5). The strand biased pyrimidine:purine repeating sequences were shown to adopt triple-stranded structures under superhelical stress or at slightly acidic pH (3).

Between the strand-biased microsatellite and GC stretches, all sequence variations retained one or two base pairs with an A residue interrupting the pyrimidine-rich strand and T interrupting the purine-rich strand. This sequence feature was highly distorted as shown by its response to nuclease enzymes (3).

Other regions of the RU sequence included variations of a symmetrical DNA sequence of alternating purines and pyrimidines shown to adopt a left-handed Z-DNA helical structure in equilibrium with a stem-loop structure under superhelical stress. The sequence CGCAC/GTGCG was repeated in one microsatellite region in all clones, and that sequence also appeared in a Z-DNA structure within RU. The palindromic sequence CGCACGTGCG/CGCACGTGCG, flanked by extended palindromic Z-DNA sequences over a 35 bp domain, adopted a Z-DNA structure with a symmetrical arrangement or alternatively a stem-loop structure centered on a palindrome containing the CGCAC/GTGCG motif (1,2,3).

Conserved sequences showed virtually no differences among cloned RU sequences. Variations among cloned RU sequences were characterized by the number of microsatellite repeats, and also by the lengths of C and G stretches where triple stranded structures formed. Other regions of variability among cloned RU sequences were found adjacent to alternating purine and pyrimidine sequences with Z-DNA/stem-loop structures (1,2,3,4,5,7,8,9).

One RU sequence was shown to have multiple copies of an Alu sequence element inserted into a region bordered by inverted repeats where most copies contained just one Alu sequence (8).

Another crab, the hermit crab Pagurus policarus, was shown to have a family of AT-rich satellites with inverted repeat structures that comprised 30% of the entire genome (6).

References[edit]

1. Fowler, R.F., L.A. Stringfellow, and D.M. Skinner (1988). A domain that assumes a Z-conformation includes a specific deletion in some cloned variants of a complex satellite. Gene 71: 165-176. 2. Fowler, R.F. (1986). Eukaryotic DNA Rich in Alternating Purines and Pyrimidines Adopts an Altered Conformation Similar to Z-DNA. The University of Tennessee, Knoxville, USA. 3. Fowler, R.F. and D.M. Skinner (1986). Eukaryotic DNA diverges at a long and complex pyrimidine-purine tract that can adopt altered conformations. J. Biol. Chem. 261: 8994-9001. 4. Stringfellow, L.A., R.F. Fowler, M.E. LaMarca, and D.M. Skinner (1985). Demonstration of remarkable sequence divergence in variants of a complex satellite by molecular cloning. Gene 38: 145-152. 5. Fowler, R.F., V. Bonnewell, M.S. Spann, and D.M. Skinner (1985). Sequences of three closely related variants of a complex satellite DNA diverge at specific domains. J. Biol. Chem. 260: 8964-8972. 6. Fowler, R.F. and D.M. Skinner (1985). Cryptic satellites rich in inverted repeats comprise 30% of the genome of a hermit crab. J. Biol. Chem. 260: 1296-1303. 7. Skinner, D.M., R.F. Fowler, and V. Bonnewell (1983). "Domains of simple sequences or alternating purines and pyrimidines are sites of sequence divergences in a complex satellite DNA" In: Mechanisms of DNA Replication and Recombination (N.R. Cozzarelli, ed.), A.R. Liss, New York. UCLA Symp. Molec. Cell Biol. 10: 849-861. 8. Bonnewell, V., R.F. Fowler, and D.M. Skinner (1983). An inverted repeat borders a fivefold amplification in satellite DNA. Science 221: 862-865. 9. Skinner, D.M., V. Bonnewell, and R.F. Fowler (1982). Sites of divergence in the sequence of a complex satellite and several cloned variants. Cold Spring Harbor Symp. Quant. Biol. 47: 1151-1157.

translation into Chinese Wikipedia[edit]

The 09:26, 1 December 2015‎ Richard.F.Fowler version of this article is translated into Chinese Wikipedia.--Wing (talk) 16:55, 5 December 2015 (UTC)[reply]

Botny[edit]

Dna satelit 2409:4063:4305:7879:8BA7:2BFB:38FE:899F (talk) 04:37, 22 March 2022 (UTC)[reply]

What is the difference between sattalite dna and sattalite cromosome[edit]

same 59.89.162.152 (talk) 00:33, 1 July 2023 (UTC)[reply]