Table 5. Proportions of OF and DCIP results in preceding generations.

Pairs	Same-tribe		Different-tribe
	n	%	n	%
Father’s and mother’s tribes
OF
Positive	23	6.3	73	8.8
Negative	343	93.7	761	91.2
χ2 = 2.10, p-value = 0.146
DCIP
Positive	9	2.5	30	3.6
Negative	357	97.3	804	96.4
χ2 = 1.04, p-value = 0.306
Both OF and DCIP positive (total = 19)	4	N/A	15	N/A
Paternal grandfather’s and grandmother’s tribes
OF
Positive	87	8.1	9	6.9
Negative	983	91.9	121	93.1
χ2 = 0.22, p-value = 0.631
DCIP
Positive	38	3.9	1	0.8
Negative	1,032	96.3	129	99.2
χ2 = 2.85, p-value = 0.091
Both OF and DCIP positive (total = 19)	18	N/A	1	N/A
Maternal grandfather’s and grandmother’s tribes
OF
Positive	13	13.3	83	7.5
Negative	85	86.7	1,019	92.5
χ2 = 4.01, p-value = 0.044*
DCIP
Positive	4	4.1	35	3.2
Negative	94	95.9	1,067	96.8
χ2 = 0.23, p-value = 0.628
Both OF and DCIP positive (total = 19)	2	N/A	17	N/A

* Significance level at α = 0.05.