In the early 2000s, Manjong Han, Xiaodang Yang, Jennifer Farrington, and Ken Muneoka investigated how genes and proteins in fetal mice (Mus musculus) influenced those fetal mice to regenerate severed toes at Tulane University in New Orleans, Louisiana. The group used hind limbs from mice to show how the gene Msx1 (Homeobox 7) functions in regenerating amputated digits. The researchers showed that in the process of regenerating digit tips, Msx1 genes make products that regulate or influence other genes, such as the Bone Morphogenetic Protein 4 gene (BMP4 gene), to produce proteins, such as the BMP4 proteins. The researchers also showed that BMP4 proteins, which are produced from the BMP4 gene, function in tissues during the process of limb development. Furthermore, while Msx1 genes regulate other genes during the process of regeneration, they don't produce proteins otherwise needed to organize cells in the regeneration of digit tissues. The group published their results in 2003 as Digit Regeneration Is Regulated by Msx1 and BMP4 in Fetal Mice.

In 2012, a team of scientists across the US conducted an experiment to find the mechanism that allowed a group of flatworms, planarians, to regenerate any body part. The group included Danielle Wenemoser, Sylvain Lapan, Alex Wilkinson, George Bell, and Peter Reddien. They aimed to identify genes that are expressed by planarians in response to wounds that initiated a regenerative mechanism. The researchers determined several genes as important for tissue regeneration. The investigation helped scientists explain how regeneration is initiated and describe the overall regenerative mechanism of whole organisms.