Why might the number of genes in eukaryotic genomes underestimate the number of different proteins that an organism makes?

• A. The genome rearranges its DNA so that different cells can make different proteins.
• B. Organisms take up foreign DNA and make proteins encoded by these foreign DNA molecules.
• C. All of the listed responses are correct.
• D. None of the listed responses is correct.
• E. Many genes undergo alternative splicing, so that different proteins with different exon combinations are produced from the same gene.

Answer: (E)

Verified step by step guidance

1. Understand that the number of genes in a eukaryotic genome does not directly equate to the number of proteins produced. This is because of processes that allow a single gene to produce multiple protein variants.
2. Learn about alternative splicing, a process where different combinations of exons are joined together to produce multiple mRNA variants from a single gene. This results in different proteins being synthesized from the same gene sequence.
3. Recognize that alternative splicing increases protein diversity without increasing the number of genes. This is a key reason why the number of proteins exceeds the number of genes in eukaryotic organisms.
4. Consider that while genome rearrangement and uptake of foreign DNA can occur, they are not the primary reasons for the discrepancy between gene and protein numbers in eukaryotes.
5. Conclude that the correct explanation for the underestimation of protein numbers by gene count is the process of alternative splicing, which allows for the production of multiple proteins from a single gene.