José M Álvarez-Castro is a mathematician and biologist by training. He studied the maintenance of variability under selection during his PhD at the University of Santiago de Compostela (Spain). He then moved to the Ludwig Maximilian University (Munich, Germany) where he inspected the interplay between selection and genetic architecture of quantitative traits, a project led by Prof. Thomas Hansen at the Florida State University (USA). During his second postdoc, he worked at Prof. Örjan Carlborg's group at the Uppsala University (Sweden), where he set up the NOIA model of genetic effects, integrating previous models under a unifying mathematical framework. He then became an assistant professor (at the Swedish University of Agricultural Sciences). Eventually, he returned to the University of Santiago de Compostela, where he kept on implementing and applying models of genetic effects and variance decomposition as PI. He spent visiting periods at several renownedinternational institutions, like the Gulbenkian Institute of Science (Oeiras, Portugal) and the Roslin Institute (University of Edinbourgh, Scotland). Currently, he has held various assignments at the Department of Education, University, and Professional Training of the autonomous administration Xunta de Galicia (Spain), while remaining connected to the University of Santiago de Compostela as an external collaborator at the Department of Statistics, Mathematical Analysis and Optimization.