Suppose expression of gene A is limited to the middle part of the early mouse embryo. Expression of gene B is located on the posterior and anterior ends of the early mouse embryo, but not in the middle. When gene B is mutated, expression of gene A is distributed over the whole embryo. What is a likely explanation for this data? Phenotypic Consequences of Gene B Mutation on Gene A Expression in Early Mouse Embryos

Phenotypic Consequences of Gene B Mutation on Gene A Expression in Early Mouse Embryos

The expression of gene A is restricted to the middle part of the early mouse embryo, while gene B is only expressed in the anterior and posterior ends of the embryo. An interesting observation is that when gene B is mutated, expression of gene A is distributed across the entire embryo. This data can be explained by the concept of gene cross-regulation, where one gene can control the expression of another gene through the interaction of regulatory proteins (Valle-Garcia et al., 2016; Lien et al., 2021). In the case of the mouse embryo, gene B may be acting as a repressor of gene A, preventing its expression in the anterior and posterior parts of the embryo. When gene B is mutated, the repression of gene A is abolished, allowing it to be expressed over the whole embryo. This is likely due to the fact that gene B does not produce a regulatory protein that can interact with other proteins and block the expression of gene A (Valle-Garcia et al., 2016; Lien et al., 2021). Cont…