Open Access

Efficient computation of the inverse of gametic relationship matrix for a marked QTL

  • Mehdi Sargolzaei1Email author,
  • Hiroaki Iwaisaki1, 2 and
  • Jean-Jacques Colleau3
Genetics Selection Evolution200638:253

Received: 27 May 2005

Accepted: 1 December 2005

Published: 26 April 2006


Best linear unbiased prediction of genetic merits for a marked quantitative trait locus (QTL) using mixed model methodology includes the inverse of conditional gametic relationship matrix (G-1) for a marked QTL. When accounting for inbreeding, the conditional gametic relationships between two parents of individuals for a marked QTL are necessary to build G-1 directly. Up to now, the tabular method and its adaptations have been used to compute these relationships. In the present paper, an indirect method was implemented at the gametic level to compute these few relationships. Simulation results showed that the indirect method can perform faster with significantly less storage requirements than adaptation of the tabular method. The efficiency of the indirect method was mainly due to the use of the sparseness of G-1. The indirect method can also be applied to construct an approximate G-1 for populations with incomplete marker data, providing approximate probabilities of descent for QTL alleles for individuals with incomplete marker data.


BLUPindirect methodinverse of gametic relationship matrixmarked QTLtabular method

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Authors’ Affiliations

Course of Environmental Management Science, Graduate School of Science and Technology
Department of Agro-biology, Faculty of Agriculture, Niigata University
Station de génétique quantitative et appliquée, Institut national de la recherche agronomique


© INRA, EDP Sciences 2006