From Spiderman and the X-men
to the Incredible
Hulk, mutants have always been turning up in comic books and
movies - but so they really exist?
The answer to this question is yes! In
fact, everyone is a mutant! New research shows that each of us
carries at least 100 new mutations in our DNA.
How do you get
mutations?
You can get them in two ways:
You can inherit mutations from your
parents. This is why some diseases can be inherited like
sickle-cell anemia.
These happen in a person's lifetime.
This is why some people have genetic diseases that they haven't
inherited from their parents.
How many
mutations do we carry in our bodies?
Way back in the 1930s, JBS Haldane, a
pioneer of mathematical genetics, guessed that we carry about 150
mutations. In those days there was no way of proving his theory.
Today, new technology has helped us find out the correct figure.
Strangely, it turns out to be between 100 and 200. John Haldane was
right!
What causes
mutations?
Mutations can be caused in many ways.
They can happen when cells are dividing. Chemicals, viruses and
radiation can also cause them.
How does radiation cause
mutations?
Types of radiation
Radiation behaves like tiny machine gun
bullets that can penetrate deeply into cells and strike the genetic
material in the nucleus. There are three types of bullets:
Alphas, betas and gamma rays are very
different kinds of bullet.
Why are the different types of
radiation more or less dangerous?
Gamma
rays
Gamma rays are the smallest bullet.
Because they are so small they can get into the body easier.
Alpha
particles
Alpha particles are BIG. They move
quite slowly so they cannot get into the body easily. They cannot
even get through the dead layer of cells on the surface of your
skin.
Beta
particles
Beta particles are much smaller than
alpha particles. They can get into the body much easier than alpha
particles. When they are on the outside of the body they make your
skin go red and can even burn sometimes. If these particles get
into your body in food, or if you breath them in they can cause a
lot of harm.
All of these types of radiation, gamma
rays, alpha and beta particles, can cause mutations. They can be
found in the natural background radiation all around us.
Can mutations be a good
thing?
Yes. Mutations are really important in
nature because without them nothing would ever change and no new
species would evolve.
Is evolution linked to
radiation?
Scientists seem to think the answer to
this is yes. Maybe the Earth has been exposed to radiation in
different time in the past and this has caused many new species to
develop through mutations.