Final answer:
The genetic code is non-overlapping, and while genes may contain regions complementary to one another influencing transcription and translation, the AUG start codon used for initiating translation typically does not overlap with coding sequences.
Step-by-step explanation:
The question addresses whether the complement of the start sequence can occur within a gene and touches on the concepts of gene expression and DNA transcription. The genetic code is non-overlapping, meaning that each nucleotide is part of only one codon and each codon corresponds to only one amino acid. Overlapping codons would severely limit the possible amino acid sequences since not all amino acids can follow one another. Therefore, an overlapping genetic code is untenable.
Regarding the start sequence in transcription, the eukaryotic initiation complex does not look for a start sequence complement within the gene but instead looks for the 7-methylguanosine cap followed by an AUG start codon based on Kozak's rules. This sequence does not typically overlap with coding sequences that would express amino acids, but rather is involved in the initiation of translation.
In the context of controlling gene expression, sequences within a gene can indeed have regions that are complementary to one another, leading to the formation of secondary structures like hairpins that can affect transcription and translation. However, this is distinct from the start sequence used for initiating translation.