In the Following Pedigree, Females and Males Are Indicated by Circles

Short Answer

In the following pedigree, females and males are indicated by circles and squares, respectively, and the presence of a rare disease caused by a loss-of-function mutation in an imprinted autosomal gene is indicated by black color. Is the gene maternally imprinted (M; i.e. not expressed from the maternally inherited chromosome) or paternally imprinted (P)? Write down M or P as your answer.