Final answer:
Copy Number Variations (CNVs) can affect phenotypes through mechanisms that extend beyond altering transcriptional units, such as disrupting regulatory elements, changing genomic architecture, and epigenetic modifications, leading to heritable and stable changes in gene expression and consequently influencing the phenotype.
Step-by-step explanation:
Copy Number Variations (CNVs) can indeed have phenotypic effects that are not directly related to the alteration of transcriptional units. Apart from changing the number of copies of genes, CNVs can impact gene expression through various mechanisms. For instance, CNVs can disrupt regulatory elements of a gene, alter the genomic architecture, or modify the chromatin environment, thus affecting the accessibility and expression of certain genes without directly modifying the gene itself. Additionally, epigenetic modifications such as DNA methylation or histone modification can change the gene expression profiles and lead to phenotypic effects, further complicating the relationship between CNVs and phenotypes. These epigenetic changes are often stable and can be heritable, impacting the phenotype across generations without altering the underlying DNA sequence.
Therefore, the phenotypic impact of CNVs can extend beyond the straightforward addition or subtraction of gene copies and can include a broad range of functional consequences through both genetic and epigenetic pathways. This expands our understanding of phenotypic variation and underscores the complexity of genomic regulation.