Middle-Range DNA Ladders (1,000–5,000 bp)

Middle-range DNA ladders covering fragment sizes from 1,000 to 5,000 base pairs (bp) serve as essential molecular weight standards for agarose gel electrophoresis, particularly useful for sizing medium-length DNA fragments such as larger PCR products, restriction enzyme digests, and cloning inserts.

These ladders typically include a series of discrete DNA fragments spaced at regular intervals within the 1 kb to 5 kb range, often extending beyond 5 kb up to 10 kb for added versatility. They commonly feature reference bands with increased intensity (e.g., at 1,000 bp and 3,000 bp) to facilitate easy orientation and accurate sizing during gel analysis.

Formulated as ready-to-load solutions or supplied with separate loading dyes, these markers are compatible with standard agarose gel concentrations (usually 0.7–1.5%) for optimal resolution of mid-sized DNA fragments. The DNA fragments in these ladders are purified and blunt-ended to ensure consistent migration patterns.

Overall, 1–5 kb DNA ladders provide reliable, well-defined standards that enable precise sizing and approximate quantification of medium-length double-stranded DNA fragments in diverse molecular biology applications.