Refer to Figure 13.7 to respond to the following:

Shown here is a hypothetical viral mRNA sequence:

 5'-AUGCAUACCUAUGAGACCCUUGGA-3'

Assuming that it could arise from overlapping genes, how many different polypeptide sequences can be produced? What are the sequences?

Key Concepts

Overlapping Genes

Overlapping genes occur when two or more genes share some of the same nucleotide sequences in their coding regions. This can lead to the production of multiple polypeptides from a single mRNA strand, as different reading frames can be utilized. Understanding how these genes overlap is crucial for determining the potential polypeptide sequences that can be generated from a given mRNA.

Reading Frames

A reading frame refers to the way nucleotides in an mRNA sequence are divided into codons, which are groups of three nucleotides that correspond to specific amino acids. There are three possible reading frames for any given mRNA sequence, depending on where translation begins. Identifying all possible reading frames is essential for predicting the different polypeptide sequences that can be synthesized from the mRNA.

Polypeptide Synthesis

Polypeptide synthesis is the process by which ribosomes translate mRNA sequences into polypeptides, which are chains of amino acids. Each codon in the mRNA corresponds to a specific amino acid, and the sequence of codons determines the order of amino acids in the resulting polypeptide. Understanding this process is vital for analyzing how many distinct polypeptides can be produced from a single mRNA sequence, especially in the context of overlapping genes.