In eukaryotes, DNA packing seems to affect gene expression primarily by __________.

• A. positioning related genes near each other
• B. protecting DNA from mutations
• C. enhancing the recombination of genes
• D. allowing unpacked genes to be eliminated from the genome
• E. controlling access to DNA

Answer: (E)

Verified step by step guidance

1. Understand that DNA packing in eukaryotes involves the organization of DNA into chromatin, which can be tightly or loosely packed.
2. Recognize that tightly packed chromatin, known as heterochromatin, is generally inaccessible to transcription machinery, thus reducing gene expression.
3. Identify that loosely packed chromatin, known as euchromatin, is more accessible to transcription factors and RNA polymerase, allowing gene expression to occur.
4. Realize that the primary way DNA packing affects gene expression is by controlling the accessibility of DNA to the transcription machinery, rather than by positioning genes, protecting from mutations, enhancing recombination, or eliminating genes.
5. Conclude that the correct answer is that DNA packing affects gene expression by controlling access to DNA, which determines whether genes can be transcribed and expressed.