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NL888 Posted 13 years ago
Grammar
How to understand "the number of copies of a repeated sequence"?
Does "the number of copies of a repeated sequence" mean "(scientists) repeatedly tested the wheat genome sequence in a very limited number of the wheat samples"?
Context:
and released it.
But pinning down the variety is difficult, says Michael Firko, the head of biotechnology regulation at the USDA’s Animal and Plant Health Inspection Service. USDA scientists have a limited amount of plant DNA to work with, and are proceeding cautiously in testing for single-base differences or variations in the number of copies of a repeated sequence that are unique to the various strains of wheat. “It takes time,” says Firko, “but we’re making good progress.”
More:
http://www.nature.com/news/hunt-for-mystery-gm-wheat-hots-up-1.13392#gmsearch
Context:
and released it.
But pinning down the variety is difficult, says Michael Firko, the head of biotechnology regulation at the USDA’s Animal and Plant Health Inspection Service. USDA scientists have a limited amount of plant DNA to work with, and are proceeding cautiously in testing for single-base differences or variations in the number of copies of a repeated sequence that are unique to the various strains of wheat. “It takes time,” says Firko, “but we’re making good progress.”
More:
http://www.nature.com/news/hunt-for-mystery-gm-wheat-hots-up-1.13392#gmsearch
Top answer
No. In genome sequencing, it means a pattern of the base pairs: ACGT along the linear chain of a DNA molecule. Certain sequences repeat, and these are significant.
- No.
- In genome sequencing, it means a pattern of the base pairs: ACGT along the linear chain of a DNA molecule.
- Certain sequences repeat, and these are significant.
- For example, a telomere sequence in a human genome is a repeating string of TTAGGG, between 3 and 20 kilobases in length.
- Apparently different strains of wheat have different numbers of these repeating sequences.
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4 Answers
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No.
In genome sequencing, it means a pattern of the base pairs: ACGT along the linear chain of a DNA molecule.
Certain sequences repeat, and these are significant. For example, a telomere sequence in a human genome is a repeating string of TTAGGG, between 3 and 20 kilobases in length.
Apparently different strains of wheat have different numbers of these repeating sequences.
In genome sequencing, it means a pattern of the base pairs: ACGT along the linear chain of a DNA molecule.
Certain sequences repeat, and these are significant. For example, a telomere sequence in a human genome is a repeating string of TTAGGG, between 3 and 20 kilobases in length.
Apparently different strains of wheat have different numbers of these repeating sequences.
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NL888variations in the number of copies of a repeated sequence1 Repeated sequence; four copies: AGGTTC AGGTTC AGGTTC AGGTTC
2 Same repeated sequence; three copies: AGGTTC AGGTTC AGGTTC
3 Same repeated sequence; five copies: AGGTTC AGGTTC AGGTTC AGGTTC AGGTTC
Take a look at the DNA sequences in 1, 2, and 3, and you find variations (difference
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Excellent! Thank you.
But the context says "single-base differences or variations in the number of copies", not just "differences or variations in the number of copies." So it gives us the question: the didderences are about the number of copies or are about the single-base differences?
AGGTTC has six bases (one A base, two G bases, two T bases and one C bases).
But the context says "single-base differences or variations in the number of copies", not just "differences or variations in the number of copies." So it gives us the question: the didderences are about the number of copies or are about the single-base differences?
AGGTTC has six bases (one A base, two G bases, two T bases and one C bases).
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NL888But the context says "single-base differences ...You're parsing it wrong.
testing for
1) single-base differences (that are unique to the various strains of wheat)
or
(testing for)
2) variations in the number of copies of a repeated sequence that are unique to the various strains of wheat.
I showed you how the
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