Authors : Zhiwu Zhang , Changxi Li , Rory J. Todhunter , George Lust , Laksiri Goonewardene and Zhiquan Wang
Abstract: Information on the additive genetic relationship among individuals in a pedigree is essential in genetic analyses for the estimation of variance components, prediction of breeding values and association mapping for Quantitative Trait Loci (QTL), so that background polygenic effects can be estimated. Calculation of the additive genetic relationship from a pedigree requires individuals to be chronologically ordered such that parents appear before their progeny. This can be accomplished by sorting individuals by their birth date. However, in practice, birth dates may not be available for some individuals due to missing records or inaccurate/errors in recording. In this study, we derived a Pyramid algorithm to obtain chronologically ordered data with the feature that parents appear before their progeny based on their parental information embodied in the pedigree. A software package (SeqPed) was developed based on the algorithm. The chronological order of individuals and the additive relationship matrix calculated from a dog pedigree based on the full birth date information was the same as those calculated from the pedigree and the chronological order obtained from the software without requiring birth date information.
Zhiwu Zhang , Changxi Li , Rory J. Todhunter , George Lust , Laksiri Goonewardene and Zhiquan Wang , 2009. An Algorithm to Sort Complex Pedigrees Chronologically without Birthdates. Journal of Animal and Veterinary Advances, 8: 177-182.