Mutations are a part of life that is often feared and seen as somehow abnormal. In reality mutations are fairly
common - they
happen in each of us. Mutations are somewhat likely to happen every time our
DNA goes through
replication or produces messenger
RNA. Luckily for us our body usually notices the mutations and fights back and corrects them.
Even though our cells have an efficient back up system against mutations some mutations still manage to "survive". In that case the mutation creates a new
allele of an existing gene in the same way that there are different alleles for different eye colours. Most of these mutations, anyhow, are harmful to the individual but some of them can actually increase its vitality. These mutations are the ones that make
evolution work. If the mutation is a positive one and it makes the individual survive better in its environment then it is very likely that the particular individual will have more offsprings than the other individuals of the same species and the new allele will spread. It's the same principle
Charles Darwin introduced in The Origin of Species. It should be remembered that the new alleles can only be passed on to the next generation if the mutation happenes in the
spermatozoa or
ovarian cells. That way the next generation will have the new allele in all of their cells, not just in the cell in which the mutation happened. So if you have a great mutation in one of your eyes which allows you to see through walls you won't be able to pass it on to your children.
Different types of mutations:
POINT MUTATIONS Point mutations consist of single
changes in the nucleotide sequence. In a
transition mutation a
purine is replaced with another purine or a
pyrimidine is replaced with a pyrimidine. In that case A becomes G and T becomes C or vice versa. In a
transversion Mutation a pyrimidine is replaced with a purine, e.g. G becomes T.
In a
missense mutation the mutation changes the
codone so that it represents a different amino acid. In a
nonsense mutation the codone changes into a termination codone.
FRAMESHIFT MUTATIONS In frameshift mutations the reading frame of a gene is changed. That can happen when one or two bases are
inserted to the genome or
deleted from it.
SUPPRESSION MUTATIONS Suppression mutations are
deletions that repair the insertions. They happen at a different spot deleting one or two bases and thus return the original reading frame.
More abstracts about the Mutations