Most commonly used inbred strain of mouse. Also known as "C57" mice or "black 6" mice. Originally developed in 1921, it should be noted that today, due to genetic drift, different C57BL/6 populations around the world are likely genetically different. Indeed, there are now specifically named substrains such as C57BL/6C, C57BL/6J or C57BL/6N.