Computing numerator relationships between any pair of animals

L.D. Van Vleck
Published September 30, 2007
Genet. Mol. Res. 6 (3): 685-690 (2007)

About the authors
L.D. Van Vleck

Corresponding author
L.D. Van Vleck


We describe a simple method to compute the numerator relationship between any or all pairs of animals in the numerator relation- ship matrix. The method depends on output of the MTDFNRM program from the MTDFREML set of programs. An option of the MTDFNRM program creates a file that includes the inbreeding coefficient for each animal. The method also makes use of how the inbreeding coefficient is traditionally calculated: one-half of the relationship between the animal’s parents. To obtain the numerator relationship between any pair of ani- mals, the original pedigree file is augmented with a dummy animal with an identification number (ID) greater than for any animal in the original pedigree file. The ID of the pair of animals for which the relationship is wanted is included as parents. MTDFNRM is then run with the option to create a file of ordered and original IDs for animals and their parents along with the inbreeding coefficients. We then multiply the inbreeding coefficient for a dummy animal by two to obtain the numerator relation- ship between the two animals designated as parents.

Key words: Inbreeding coefficient, Pairs of animals, Numerator relationships

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