DNA was first isolated from white blood cells in the 1860s by:

1. The molecule was purified decades before anyone knew what it did. 2. DNA was first isolated from white blood cells by Miescher in the 1860s. 3. He named these chemicals nuclein because they were isolated from the nuclei of the cells. 4. Griffith's transformation work came more than fifty years later. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 14 'DNA Structure and Function', sections 14.1-14.6_