B.7C Mutations on level – 02
It was a lazy Saturday evening and Ethan was watching a movie about superheroes. As he watched he wondered can mutations really give superpowers? At school, they are studying the DNA and he knows that DNA is transcribed to RNA and then translated to form a protein. If there is a change in your DNA, there will be a change in the protein produced, and therefore there will be a change in…you! So, is it possible…? He decided to ask his neighbor, Dr. Wallace, who teaches genetics at the local University.
On Sunday, Ethan could hardly contain his excitement as Dr. Wallace sat down with him and began to explain.
Dr. Wallace said that mutations were simply changes in the DNA that alter the genetic message. Most mutations may have no effect on the organism, some can be beneficial and others can negatively affect the function of a gene. In fact, he said that the diverse forms of life that we see today are essentially due to changes in the DNA or in other words mutations.
DNA is read in a sequence of three bases. Each of these sequences is a codon. Sequencing of bases is like writing a sentence. For example, continued Dr. Wallace, if few of the letters in the sentence, “THE MAN SAW THE FAT DOG.” was changed by chance, would you be able to understand the message? Probably not. Similarly, when there is a mutation, the message in the DNA is altered.
There are two basic forms of mutations. One form is a gene mutation, or a change in the nucleotide sequence of the gene. The other form is a chromosomal mutation, or a change in large segments of the chromosomes.

Mutation at a single point in the nucleotide base are point mutations. Substitution is one type of point mutation where one base is changed into a different base. Depending on the point of substitution, the mutation may or may not have any effect. For example, a change in the third base from CAU to CCA would still produce the same protein histone, but a change in the first base from U to C would produce a completely different protein tyrosine, and could therefore have a significant effect.