Answer:
The methyltransferases methylate their substrates. This methylation influences the stability of the gene, its transcription, and parental imprinting. It straightforwardly influences the chromatin composition and can modify gene transcription. On certain occasions, methylation can silence the genes completely or can activate the genes, without mutating the gene. Therefore, the features related to the expression of these methylated genes will be getting changed.
Thus, if the knocking of RNA methyltransferase A takes place in mice, it will lead to the changes in some of the ovarian activities. As ovary is the internal organ, its functional modifications may or may not influence the other phenotypic characteristics of mice, a phenotype is the overall outward expression, and not of one internal organ.