Table 8. Example coding for the within-family test for association between deafness and speckling.
Individual | Deaf* | Speckled* | Adjusted Deafness | Adjusted Speckling |
Dog 1 | 0 | 0 | −0.5 | −0.25 |
Dog 2 | 1 | 0 | 0.5 | −0.25 |
Dog 3 | 1 | 1 | 0.5 | 0.75 |
Dog 4 | 0 | 0 | −0.5 | −0.25 |
Mean | 0.5 | 0.25 |
Coding: 0 = absent, 1 = present.
The adjusted values are calculated by subtracting the family mean from the phenotypic value. The correlation between the adjusted values is a robust test of genetic association between the traits.