Why might there be more than 423 bases in the DNA of a polypeptide gene?

The presence of more than 423 bases in the DNA of a polypeptide gene can be attributed to several factors that highlight the complexity of genetic sequences.

One significant reason is the inclusion of non-coding regions and introns within the gene. In eukaryotic organisms, genes often consist of coding regions (exons) that are expressed and translated into proteins, interspersed with non-coding regions (introns) that are not translated. During gene expression, introns are typically spliced out of the pre-mRNA, but they still contribute to the overall length of the gene when considering the genomic DNA.

Additionally, the existence of multiple start and stop sequences can affect the gene length as well. While a single polypeptide generally has one start codon and one stop codon, variations in regulatory sequences may lead to different transcription or translation initiation points in different contexts, potentially resulting in more bases being counted within the coding sequence.

Furthermore, mutations can also play a role in altering the length of a gene, either by inserting additional bases that may shift the reading frame or by affecting sequences that regulate gene function. These mutations can lead to an increase in the number of bases present in the genomic sequence.

Collectively, these factors illustrate