Mutation Vs polymorphism - Mutation Vs Polymorphism (Apr/05/2006 )

Hi there all

its an old question, but one that does not seem to have a consensus in terms of a precise definition. What is the difference between polymorphism Vs mutation?

I need verification to MY understanding.. and if im wrong could i be corrected please. THankyou


Yes both are changes but is it more truthful to explain it as:

a mutation: is induced from outside the cell: by an exogenous factor, is inheritable and
will not necessarily be harmful to the host. Therefore a mutation is individualised and
will occur in less than 1% of the population.


A polymorphism: is induced from within the cell( i.e. through evolution the cell changes to conform
to the changing environment to survive...(after all the basic function of a cell is to
use all its various pathways and mechanism to survive, thereby maintaining
its function within the host.)), is heritable but is not necessarily harmful to the
host. This heritable change will occur in at least 1% of the population.

If examples had to be given , which examples will be classified under mutations and which under polymorphism.??

Thankyou for your help

143

in a nut shell "yes": the key point is the prevalance in the population, polymorphisms are those found in a significant proportion of the population, whereas mutations are not.

I've been recently informed that according to Nature Genetics, it is the prevelance in a population thats the key, along with its disease causing tendencies.

Just to make a pedantic point, polymorphisms can also be inherited and associated with disease, but cannot directly cause the disease

Again it come down to frequency in the population, cancerous mutations (even common one such as BRAC-1) occur in less than 1% of the population, therefore most diseases are associated with the term mutations - as it is higly unlikely that a disease causing mutation will persist in more than 1% of the population.

While the term polymorphisms is normally associated with other inherited factors that either are beneficial or null, as you would expect these polymorphisms can easily occur in over 1% of the population.

Thus in the end the prevelence of the mutation in the population decides what term is given - but i would say you are safe to associate diseases with mutations.

And interesting aside, would be in a population subset where a disease causing mutation actually confers an advantage and thus occurs at higer levels in the population ie. over 1% such as some areas in africa where sickle cell anemia confers resistance to malaria, in this case well I believe it will be a polymorphism as by definition it occurs in over 1% of the population

In popgen, a mutation is described as a one time single event, while a polymorphism is a mutation that was able to increase in frequency within the population..
More precisely, if the frequency of appearance of the "variant" is higher that neutral equilibrium population mutation rate, it is a polymorphism.