Researchers used a method called SDS-PAGE to compare the seed proteins of two types of forage plants, Lotus tenuis and Lotus corniculatus. They found that the two species have different protein profiles, with 22 main protein bands for Lotus tenuis and 18 for Lotus corniculatus. By looking at the presence or absence of specific bands and their intensity, they could distinguish between the two species. Even when the seeds were mixed together, the SDS-PAGE method was still able to identify which species were present.