Fossils show that limbs evolved from fins, and a new study reveals how it may have happened. Spanish scientists injected a zebrafish with the gene hoxd13, which is from a mouse. (It is also naturally found in the fish but is not expressed as aggressively.) Within 24 hours, all the embryos were developing autopods instead of fins. Researchers believe this could be a first step toward human limb production.
View the original article here: From Fish to Human: Research Reveals How Fins Became Legs