The primary objective of this proposal is to clarify the origins of Indo-European populations. This is a very important topic which is at the interface of paleoanthropological studies using fossil materials and genetic studies drawing upon gene frequency data. There are currently two competing theories about the origin of these populations and the spread of agriculture from the Middle East. One view holds that the people themselves migrated westward, bringing the new technology with them. The other holds that the technology spread by diffusion without the movement of people. The computer simulations proposed here will help to decide between these competing views.