Which laboratory method is most useful for separating genomic DNA fragments by size?

Titration is a quantitative chemical analysis method used to determine the concentration of a solute in a solution. It involves the gradual addition of a titrant to a solution until a reaction reaches completion, which is not applicable for separating DNA fragments based on size. Thus, it does not serve the purpose of separating genomic DNA.

Spectrophotometry measures the amount of light absorbed by a substance at specific wavelengths to determine concentration and purity. While it is useful for assessing DNA quality, it does not separate DNA fragments by size, making it unsuitable for this purpose.

Filtration is a physical separation process that removes particles from liquids or gases using a porous material. Although it can separate components based on size, it is not effective for the separation of DNA fragments, which typically require a medium like gel to achieve the desired resolution based on size differences.