The phrase "a small section of DNA" is correct and usable in written English.
It can be used in scientific or educational contexts when discussing genetics, molecular biology, or related fields.
Example: "Researchers identified a small section of DNA that is responsible for the inherited trait."
Alternatives: "a minor fragment of DNA" or "a tiny piece of DNA."
The gene is carried on a plasmid, a small section of DNA that can move from one bug to another, passing on drug-resistance as it goes.
This can occur by one of two methods: 'crossover events' that produce a final chromosome made up of long sequences from each of the contributing chromosomes; and 'non-crossover events', where only a small section of DNA is swapped between the chromosomes.
Normally only a small section of the DNA is transcribed.
Marine conservation biologists and geneticists Joe Roman of Harvard University in Cambridge, Massachusetts, and Steve Palumbi of Stanford University in California used databases of a small section of mitochondrial DNA (mtDNA) to reconstruct population histories for humpback, minke, and fin whales mostly in the North Atlantic.
Total genomic DNA was extracted from a small section of thallus material using the Prepease DNA Isolation Kit (USB, Cleveland, Ohio, USA), following the plant leaf extraction protocol.
Geneticists have previously made estimates of the human-chimp lineage split, chiefly by drawing up a primate family tree, based on the number of DNA differences in a small section of the genome, and then anchoring the tree to some well-attested date in the fossil record, like the split between orangutans and the other primates.
On a small section of chromosome 9, the mutation appears to cause a DNA fragment that normally recurs a handful of times to repeat itself hundreds to thousands of times.
They say the events described in the Book of Mormon were confined to a small section of Central America, and that the Hebrew tribe was small enough that its DNA was swallowed up by the existing Native Americans.
Especially yesterday, in a small section of Midtown Manhattan.
A small section of the wall is sectioned off for women.
Only a small section of the aforementioned pigeon swarm.
