Final answer:
Epigenetic changes do not alter the DNA sequence but can impact gene expression through modifications like histone acetylation and DNA methylation. These changes can be heritable, allowing the influence of an organism's environment to span generations.
Step-by-step explanation:
Epigenetic changes refer to modifications that affect gene expression without altering the underlying DNA sequence. They are a crucial aspect of how organisms can adapt to environmental stimuli and even involve mechanisms that can sometimes be heritable across generations. Among the false statements about epigenetic changes are that they alter the DNA sequence and are always caused by mutations. Instead, epigenetic modifications occur through processes such as histone acetylation and DNA methylation, which lead to changes in chromatin structure and thus impact transcription accessibility.
Specifically, when histone proteins undergo acetylation, there is a loosening of the nucleosomes, which facilitates transcriptional access. Alternatively, the addition of more nucleosomes or different chemical modifications can lead to a closed chromosomal configuration, preventing the initiation of transcription. Although these modifications are not permanent, they can be stable enough to pass through cell divisions and potentially be transmitted to offsprings, affecting their phenotypes.