Given these advantages of focusing on specific populations, populations of European descent were a natural choice for early GWA studies. Several European populations with a strong history of human-genetic research — such as the populations of Finland, Iceland, and Sardinia — are large enough that it was possible to conduct studies with large samples in the setting of a comparatively homogeneous population. In addition, extensive collaborations and long-term genetic studies had already been established involving investigators from European countries and from non-European countries with large populations of European descent, such as Australia, Canada, and the United States.
