The two gels illustrated contain dideoxynucleotide DNA-sequencing information for a wild-type segment and mutant segment of DNA corresponding to the N-terminal end of a protein. The start codon and the next five codons are sequenced. Write the DNA sequence of both alleles, including strand polarity.

Verified step by step guidance

1. <Step 1: Understand the context of the problem. You are given two DNA sequences obtained from dideoxynucleotide sequencing gels, one for a wild-type and one for a mutant segment. These sequences correspond to the N-terminal end of a protein.>
2. <Step 2: Identify the start codon in the sequence. The start codon for protein synthesis is typically 'ATG' in DNA. Locate this codon in both the wild-type and mutant sequences.>
3. <Step 3: Determine the directionality of the DNA strands. DNA sequences are typically read from the 5' to 3' direction. Ensure you identify the 5' and 3' ends of the sequences on the gel.>
4. <Step 4: Transcribe the sequence from the gel. Using the information from the gel, write down the sequence of nucleotides for both the wild-type and mutant alleles, ensuring to include the strand polarity (5' to 3').>
5. <Step 5: Compare the sequences. Once you have both sequences, compare them to identify any differences between the wild-type and mutant alleles, which may affect the protein's N-terminal end.>

Key Concepts

Dideoxynucleotide Sequencing

Dideoxynucleotide sequencing, also known as Sanger sequencing, is a method used to determine the nucleotide sequence of DNA. It involves incorporating dideoxynucleotides, which terminate DNA strand elongation, allowing for the generation of fragments of varying lengths. By analyzing these fragments through gel electrophoresis, researchers can deduce the sequence of the original DNA strand based on the size of the fragments.

Codons and Genetic Code

Codons are sequences of three nucleotides in DNA or RNA that correspond to specific amino acids or stop signals during protein synthesis. The genetic code is universal and dictates how sequences of nucleotides are translated into proteins. Understanding codons is essential for interpreting the DNA sequence and predicting the resulting protein structure and function.

Strand Polarity

Strand polarity refers to the orientation of the DNA strands, which are antiparallel and have distinct 5' and 3' ends. The 5' end has a phosphate group, while the 3' end has a hydroxyl group. This polarity is crucial for DNA replication and transcription, as enzymes that synthesize DNA and RNA can only add nucleotides to the 3' end of a growing strand, influencing how sequences are read and written.