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 types of DNA make up the rest of the human genome?
A) DNA that consists of histone coding sequences
B) DNA that is translated directly without being transcribed
C) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function
D) non-protein-coding DNA that serves as binding sites for reverse transcriptase

Question

Quizplus · Accepted Answer

The non-protein-coding DNA that makes up the majority of the human genome is transcribed into various types of small RNAs, including microRNAs and long non-coding RNAs, that have important biological functions such as gene regulation and chromatin remodeling. Histone coding sequences (A) are only a small fraction of the genome, and DNA that is translated directly without being transcribed (B) does not exist in eukaryotes. While some non-protein-coding DNA may serve as binding sites for reverse transcriptase (D), this is not a major component of the human genome.

At the Beginning of This Century, There Was a General