title: Identification of gametes and treatment of linear dependencies in the gametic QTL-relationship matrix and its inverse.
abstract: The estimation of gametic effects via marker-assisted BLUP requires the inverse of the conditional gametic relationship matrix G. Both gametes of each animal can either be identified (distinguished) by markers or by parental origin. By example, it was shown that the conditional gametic relationship matrix is not unique but depends on the mode of gamete identification. The sum of both gametic effects of each animal--and therefore its estimated breeding value--remains however unaffected. A previously known algorithm for setting up the inverse of G was generalized in order to eliminate the dependencies between columns and rows of G. In the presence of dependencies the rank of G also depends on the mode of gamete identification. A unique transformation of estimates of QTL genotypic effects into QTL gametic effects was proven to be impossible. The properties of both modes of gamete identification in the fields of application are discussed.
authors.affiliation: Forschungsinstitut für die Biologie landwirtschaftlicher Nutztiere, Forschungsbereich Genetik und Biometrie, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Tuchscherer
authors.forename: Manfred
authors.initials: M
authors.lastname: Mayer
authors.forename: Norbert
authors.initials: N
authors.lastname: Reinsch
mesh_terms: D000465:Algorithms; D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D005718:Gametogenesis; D008040:Genetic Linkage; D005819:Genetic Markers; D005828:Genetics, Population; D005854:Germ Cells; D007178:Inbreeding; D016014:Linear Models; D008297:Male; D008957:Models, Genetic; D015233:Models, Statistical; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable
chemical_list: D005819:Genetic Markers