There are four bases forming part of the DNA: cytosine, adenine, thymine, and guanine. The bases link to form a nucleotide. This comprises of a pentose sugar, an organic base and a phosphate group. Each combination of these nucleotides is a codon. The sequencing of nucleotides affects the amino sequence since each codon is translated into a different amino acid. This means that each combination represents a different amino acid (McConkey 24).
Addition or deletion of a single nucleotide somewhere in the sequence results in formation of different amino acids from the point of addition. This is because the addition or deletion affects the polypeptide-coding segments. A ripple effect occurs whereby the reading frame is also affected. Therefore, the amino acid sequence from the point of change is completely different from the initial amino acid sequence (Chapman 36).
Cystic fibrosis (CF) is a mutation due to encoding of genes of the CF trans-membrane conductance. CFTR is a protein present in several types of cells such as in the pancreas, liver, and lung epithelium. It occurs due to deletion of phenylalanine from its normal position. This is commonly referred to as F508del.
The number of nucleotides in the CFTR gene is six. This is because the codon consists of three bases formed from left to right of the DNA strand (TAG TAG AAA GGT GTT ATC). TAG is a stop codon while AAA codes for lysine. GGT codes for glycine , GTT codes for valine while ATC codes for isoleucine. DNA is plays a central role in the manufacture of amino acids. Therefore, protein synthesis is dependent on the DNA(Grody 149).
Works cited
McConkey, Edwin. How the Human Genome Works. London. Jones & Bartlett Learning.
(2004).pdf.
Grody, Wayne, et.al. Molecular Diagnostics. London. Academic Press. (2009).pdf.
Chapman. Mass Spectrometry of Protein and Pepetides. New Jersey. Humana Press. (2000).pdf.
