The answer depends on what is claimed. For a patent several conditions should be met. Apart from novelty, inventive step, enabling disclosure, clarity and statutory subject matter, a condition is industrial applicability (see proceedings patent workshop Jaenichen page 11 and 12).

The industrial applicability of the modified piece of DNA might be, that it provides breeders, producers, and retailers with an improved method of selecting the best animals for their purposes. The utility of the DNA is not the genetic merit of the DNA, but in the invention of placing this easily selected sequence next to a gene of economic importance.