Researchers Take a Tissue Sample (image) Smithsonian Caption Researchers Gracia Gonzalez-Porter (left) and Rene Calderon take a tiny tissue sample from between two of the rear toes of a Central American river turtle from the Belize River. Credit Photo courtesy of Gracia González-Porter Usage Restrictions Please include photo credit when using the photo. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.