More than likely mutation
embryonic stem cells could serve as a model to evaluate the physiological effects of environmental pollutants efficiently and cost-effectively.
Answer:
Silencer
Explanation:
Silencers are the position and orientation free sequences that are present outside the protein-coding sequence of a gene. Silencers serve as a binding site for some transcriptional regulatory proteins that tend to inhibit gene expression. Binding of these "repressor" proteins to the silencers inhibits the gene expression.
The deletion of silencers from DNA would increase the rate of the gene expression as the inhibitory transcription regulatory proteins do not have binding sites to inhibit the gene expression. Therefore, the deletion of silencer sequences of the beta-globin gene would have caused the increased rate of its expression.
