Deciphering dairy cattle genomics

PhD defense, 19 October 2018. Andrew Gitahi Marete.

2018.10.19 | Olivia Elsebeth Belling-Nami

Andrew Gitahi Marete.

During his studies, Andrew Gitahi Marete researched the various methods of validating candidate variants that can contribute towards increased genomic gains in dairy cattle. Using bioinformatics and statistical approaches, and a combination of data from 50k SNP-chip array variants and pre-selected whole genome sequence variants, he studied various methods of selecting candidate genes. In theory, since sequence data contains variants that directly influence quantitative traits and variants strongly linked to them, validating such variants could improve the accuracy of genomic selection.

Furthermore, Andrew Gitahi Marete investigated additive, dominance and epistasis variation as explained by variants with a major effect. Dominance variance was consistent across breeds and traits and represented about 20% of the additive genetic variance. The epistatic variance estimates were more variable with an average of 7% and a maximum of 19% of the additive genetic variance across the breeds and traits. The results show that pre-selected sequence variants have the potential to improve genomic prediction, and accounting for non-additive variances could further augment this improvement. 

Andrew Gitahi Marete completed the Ph.D. degree at the GABI unit at AgroParisTech and INRA, and the Center for Quantitative Genetics and Genomics, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University.

This resume was prepared by the PhD student

Time:  Friday 19. October 2018 at 14.00
Place : 16 rue Claude Bernard, AgroParisTech, Paris, France
Title of dissertation: Use of large-scale cow genotyping to dissect dairy complex traits beyond additive effects
Contact information: Andrew Gitahi Marete, e-mail:, tel.: +4571567719

Members of the assessment committee:
Professor Etienne Verrier, UMR GABI, AgroParisTech, France
Professor Just Jensen, Aarhus University, Denmark
Professor Henk Bovenhuis, Wageningen University, Netherlands
Professor Rainer Roehe, Scotland’s Rural College, United Kingdom
Professor Christa Kühn, Leibniz Institute for Farm Animal Biology, Germany
Dr. Christèle Robert-Granié, Deputy Director and Senior Scientist, GenPhySE INRA, France
Dr. Aurélien Capitan, Senior Scientist, ALLICE, France

Main supervisors:
Senior Scientist Dr Didier Boichard, UMR GABI, INRA, France
Professor Mogens Sandø Lund, Department of Molecular Biology and Genetics, Aarhus University

Language: The Ph.D. dissertation will be defended in English

The defense is public.

The dissertation is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, buildings 1520 and 1521, 8000 Aarhus C.

PhD defence
Comments on content: 
Olivia Elsebeth Belling-Nami

Revised 22.10.2018