From completing life-saving surgeries, to performing heart-gripping music, to fearlessly swimming the English Channel, the possession of paired appendages (arms and legs) is critical to human achievement. However, paired appendages are not unique to humans. Scientists have long known that human limbs evolved from the paired fins found in fishes, but where the first paired fins came from remains one of the great mysteries in evolutionary biology. Visiting Assistant Professor of Biology Amanda Cass was a co-author of a large, multi-institutional study published in the journal Nature investigating how paired appendages evolved in early vertebrate animals. The study, spearheaded by…