Final answer:
Presence of enhancer sequences (option B) typically leads to an increase in transcription because they facilitate the binding of transcription factors that increase RNA polymerase affinity to promoter regions, thus increasing gene expression.
Step-by-step explanation:
In biology, particularly genetics, it's important to understand how transcription is regulated. To determine which events lead to an increase in transcription, we can consider the impact of various factors. Enhancers, such as enhancer sequences, promote gene transcription by facilitating the binding of transcription factors. When transcription factors bind to enhancers, they can increase the affinity of RNA polymerase to promoter regions, which results in increased transcription of associated genes.
The binding of repressor proteins typically decreases transcription, as these proteins inhibit the binding of RNA polymerase to DNA. On the other hand, the methylation of DNA can have varying effects on gene expression; in some cases, it can repress transcription, while in others, it may increase transcription if it facilitates regulatory protein-enhancer binding.
Given this information, only the presence of enhancer sequences typically leads to an increase in transcription, making option B the correct choice among the provided options.