What is a functional genome?

A functional genome refers to the complete set of functional elements present in the genome, which includes genes that encode proteins as well as regulatory sequences that control the expression of those genes. This concept encompasses not just the protein-coding regions but also non-coding regions that play crucial roles in regulating gene activity, such as enhancers, silencers, and promoters. Understanding the functional genome is essential for grasping how various parts of the DNA contribute to the overall biology of an organism, including development, response to environmental signals, and the maintenance of cellular functions.

The other options do not encapsulate the full concept of a functional genome. While non-coding DNA indeed plays a role in gene regulation, defining the functional genome solely by the presence of non-coding DNA fails to include coding genes themselves, making it incomplete. A collection of mutations within a population refers to genetic diversity and variations, not the overarching functionality of genome elements. Lastly, the total number of chromosomes simply describes a structural aspect of the genome and does not provide insight into its functional components.