Question

Bacteria have a high mutation rate comlared to animals. Please explain what is being mutated and how. will each mutation kead to a noticeable change in the organism?

Answer 1

The genetic sequence of bacteria is actually mutated here, due to errors in DNA replication process. Bacteria mutates at high rates because their replication cycles are really short. Bacteria can duplicate within few minutes to few hours. That is sometimes even faster than the time taken to duplicate it’s entire genome which is done by starting the next replication before the first cycle is even completed.

Mutation can occur in following ways :

1- Substitution : When a nucleotide is replaced by another nucleotide. Hence it can cause the formation of entirely different protein.

2- Insertion : When extra nucleotide(s) are inserted between the existing nucleotides.

3- Deletion : When existing nucleotide(s) are lost or deleted from the sequence

4- Frameshift : Protein-coding DNA is divided into codons three bases long, insertions and deletions can alter a sequence so that it is no longer correctly parsed, hence causing different reading frame which will ultimately code an entirely different protein.

All the above mentioned mutations occur during errors in DNA replication or due to fragmented/damaged genome.

Secondly, all mutations don't necessarily lead to noticable changes in organism. Most of the mutations are not visible, hence referring them to as Silent Mutations. Only a small percentage of mutations have visible effects on the organism.