The phrase "a relatively small stretch" is correct and usable in written English.
It can be used to describe a distance or duration that is not large in comparison to something else, often in a figurative sense.
Example: "The hike to the summit was a relatively small stretch compared to the long journey we had taken to reach the base."
Alternatives: "a fairly short distance" or "a modest length".
The rerouting would have affected a relatively small stretch of the No. 5 line.
The beach is a relatively small stretch of creamy shingle, backed by a cluster of small restaurants and pensions, while the countryside around has a lush beauty; pine forests mixed with oak, myrtle and carob trees.
However, a limited number of water pollutants and a relatively small stretch of highway were considered in the present study.
Then the scientists can search the stick a relatively small stretch of DNA for the relevant gene.
First, the method we describe here to generate an RMCE knock-in allele requires only the cloning of relatively small stretches of DNA (the homology arms); in (Wesolowska and Rong 2013) the entire locus was cloned.
We find that ORF fragmentation has the potential to dramatically cause false-negatives in some annotation types, especially those relying on relatively small stretches of sequence (e.g., Pfam domains; Table 1).
Strong winds from the storm were confined to a relatively small area, stretching from Key Largo to about Miami Beach.
Back then, the club was formally incorporated on a relatively small and barren stretch of land beside the Genesee River in Western New York.
An 18-game stretch is a relatively small sample, but the Yankees had not been overly impressive in a slightly larger one, either.
By comparison, Ms. Boyland's Council district includes a relatively small part of the Congressional district, which stretches from Brownsville to Park Slope and Brooklyn Heights.
Her district includes a relatively small portion of the Congressional district, which stretches from Brownsville to the Park Slope and Brooklyn Heights sections of Brooklyn.
