also known as physical anthropology, examines the biological traits of humans past and present, and how these traits interact with cultural factors to produce human variation through time and across space. Biological anthropologists also study the evolutionary origins of the human species from non-human primates that began many millions of years ago. Traditionally, biological anthropologists relied mainly on fossilized skeletal remains for their studies. Recently, however, advances in the field of genetics have enabled them to examine ancient DNA for clues to our origins. A related field focuses on primatology, the study of the behavior and biological traits of modem apes and monkeys in order to gain greater understanding of our distant ancestors. In the contemporary world, forensic anthropology, which deals with the application of biological anthropology methods to legal issues (e.g identification of crime victims), is a very dynamic branch of biological anthropology. In common with the other three subfields of anthropology, biological anthropology uses the comparative method to test the boundaries between the culturally constructed and the biologically determined.