Genetic inbreeding depression load for morphological traits and defects in the Pura Raza Española horse
Poyato-Bonilla, Julia (Universidad de Sevilla. Departamento de Ciencias Agroforestales)
Perdomo-González, Davinia I. (Universidad de Sevilla. Departamento de Ciencias Agroforestales)
Sánchez-Guerrero, María J. (Universidad de Sevilla. Departamento de Ciencias Agroforestales)
Varona, Luis (Universidad de Zaragoza. Departamento de Anatomía, Embriología y Genética Animal)
Molina, Antonio (Universidad de Córdoba. Departamento de Genética)
Casellas Vidal, Joaquim (Universitat Autònoma de Barcelona. Departament de Ciència Animal i dels Aliments)
Valera, Mercedes (Universidad de Sevilla. Departamento de Ciencias Agroforestales)

Date:	2020
Abstract:	Inbreeding is caused by mating between related individuals and is associated with reduced fitness and performance (inbreeding depression). Several studies have detected heterogeneity in inbreeding depression among founder individuals. Recently, a procedure was developed to predict hidden inbreeding depression load that is associated with founders using the Mendelian sampling of non-founders. The objectives of this study were to: (1) analyse the population structure and general inbreeding, and (2) test this recent approach for predicting hidden inbreeding depression load for four morphological traits and two morphology defects in the Pura Raza Española (PRE) horse breed. The regression coefficients that were calculated between trait performances and inbreeding coefficients demonstrated the existence of inbreeding depression. In total, 58,772,533 partial inbreeding coefficients (F ) were estimated for the whole PRE population (328,706 horses). We selected the descendants of horses with a F ≥ 6. 25% that contributed to at least four offspring and for which morphological traits were measured for the subsequent analysis of inbreeding depression load (639 horses). A pedigree was generated with the last five generations (5026 animals) used as the reference population (average inbreeding coefficient of 8. 39% and average relatedness coefficient of 10. 76%). Heritability estimates ranged from 0. 08 (cresty neck) to 0. 80 (height at withers), whereas inbreeding depression load ratios ranged from 0. 01 (knock knee) to 0. 40 (length of shoulder), for an inbreeding coefficient of 10%. Most of the correlations between additive and inbreeding depression load genetic values and correlations between inbreeding depression load genetic values for the different traits were positive or near 0. Although the average inbreeding depression loads presented negative values, a certain percentage of the animals showed neutral or even positive values. Thus, high levels of inbreeding do not always lead to a decrease in mean phenotypic value or an increase in morphological defects. Hence, individual inbreeding depression loads could be used as a tool to select the most appropriate breeding animals. The possibility of selecting horses that have a high genetic value and are more resistant to the deleterious effects of inbreeding should help improve selection outcomes.
Grants:	Ministerio de Economía, Industria y Competitividad AGL-2017-84217-P
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Genetics, selection, evolution, Vol. 52 (october 2020) , ISSN 1297-9686

DOI: 10.1186/s12711-020-00582-2
PMID: 33081691

12 p, 1.3 MB

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