A. Baer, Ph.D.
This is a story of genetic and cultural history. While Borneo cultures have been well studied, their human genes have not. Human genes have been better studied in two nearby areas, the Philippines and the Malaysian Peninsula. Genes have been understudied in Borneo largely because it has few research institutions. This is related to the fact that Borneo is thinly populated and until recently had few urban conglomerations.
Even with the genetic studies that do pertain to Borneo, uncertainties remain. First, the people that have been surveyed have not always been carefully identified in cultural terms. Second, most work today on the genetic material, familiarly called DNA, focuses on bits scattered between the genes along the DNA strand. These bits are easier to analyze than genes but are less informative about what makes us human.
In broader terms, the structure of populations has a powerful effect on the level of gene variation in a group and on its differences from other groups. Here demography, historical data, and anthropology play a crucial role in analyzing the biological heritage of Borneo in the real world---as opposed to abstract genetic models.