At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. Many people were surprised that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for much of the DNA that is NOT coding for proteins?
A) most of the DNA serving as origins of DNA replication
B) DNA that consists of histone coding sequences
C) DNA that is translated directly without being transcribed
D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function
E) non-protein-coding DNA that serves as binding sites for reverse transcriptase

Question

Quizplus · Accepted Answer

Non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function can account for much of the DNA that is not coding for proteins. These small RNAs play important roles in gene regulation, chromatin remodeling, and other cellular processes. The other options, such as origins of DNA replication, histone coding sequences, and binding sites for reverse transcriptase, do not account for a significant amount of non-coding DNA. DNA that is translated directly without being transcribed is a hypothetical scenario and does not occur in cells.

At the Beginning of This Century There Was a General