What term refers to noncoding, intervening sequences within a eukaryotic gene?

The correct term for noncoding, intervening sequences within a eukaryotic gene is "introns." Introns are segments of a gene that are transcribed into pre-mRNA but are not translated into protein. During the process of gene expression, introns are removed from the pre-mRNA during RNA splicing, allowing the coding sequences, or exons, to be joined together to form the final mRNA transcript. This highlights the function of introns in gene regulation and the complexity of eukaryotic gene expression, as they can play roles in alternative splicing and potentially influence the diversity of proteins produced from a single gene.

In contrast, codons refer to sequences of nucleotides in mRNA that are translated into amino acids, and exons are the coding regions of a gene that are retained in the final mRNA. Promoters are regions of DNA that initiate transcription of a particular gene, but they do not contain the sequences that are ultimately translated into protein. Understanding these terms is crucial for grasping the intricacies of molecular biology and genetic expression.