This is particularly so in Chad, where the openness of the terrain, marginal rainfall, frequent drought and famine, and low population densities have encouraged physical and linguistic mobility.

Although most ethnic groups emphasize intermarriage, people are often proscribed from seeking partners among close relatives—a prohibition that promotes biological variation.

With the exception of a few surveys conducted shortly after independence, little data were available on this important aspect of Chadian society.

The peoples of Chad carry significant ancestry from Eastern, Central, Western, and Northern Africa.

The presence of such different languages suggests that the Lake Chad Basin may have been an important point of dispersal in ancient times.

[2] The separation of religion from social structure in Chad represents a false dichotomy, for they are perceived as two sides of the same coin.

Observers report that Islam has spread among the Hadjarai peoples and other non-Muslim populations of the Saharan and sahelian zones.

In addition, the upheavals since the mid-1970s have resulted in the departure of some missionaries; whether or not Chadian Christians have been numerous enough and sufficiently organized to attract more converts since that time is unknown.