Common cases that the GRM doesn’t invert
Published:
Here, I show common genetic reasons where can lead to genomic relationship matrix (GRM) with problems in the inversion. They are commonly based on population structure or repeated (or highly similar) information. The cases are not always true, but they can represent why you have a strong linear dependence in your G matrix (Van Raden 2008) and a not unique inverse for the matrix. After identifying the reason, you can take action in order to manage the data before building the G matrix.