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ver. 0.001          mtDNA Mutation Computer Model          ©2005 Ian Logan

                          Initial Mutation %.                     Cell Population No.                 Runs


To use the mtDNA Mutation Computer Model, simply press START.
The Initial Mutation % and the Cell Population No. can be varied.
After any alteration, press START again. Use CLEAR to erase an earlier report, if wished.

The mtDNA Mutation Computer Model shows that a mutation will often become established
if the Initial Mutation % is at 2%, or higher, but only rarely so if set to 0.5%, or below.


This computer model has been written to show how mutations become established in mitochondria.

Mitochondrial behaviour is very different to that of the chromosomes as they still retain
characteristics that show their presumed 'bacterial' origin.
And, a single cell has a number of mitochondria, maybe 1-2000, that act as independent organelles.

There are two processes that are important:
(1)Mitochondria multiple by simple 'division'.
(2)Mitochondria distribute themselves, at random, into the 'daughter' cells as a cell divides.

In this mtDNA Mutation Computer Model the user can set an Initial Mutation %
which can be considered as the level of mutations in an 'Egg' cell before fertilisation.

It is also possible to vary the Cell Population No. which is the number of cells
into which the mitochondria may go after an 'Egg' has been fertilised.

The number of 'Runs' can be varied between 10 and 100.

A 'fertilised Egg' is considered as dividing a number of times as a 'blastula' is formed
with just one of the cells going on in due course to form, in a female, the 'Eggs'.

In this Computer Model it is taken that a cell has 1000 mitochondria which are passed to the
cells of a 'blastula'. The mitochondria are 'distributed are random' - but this 'distribution' is 'discrete',
- by which is meant, each mitochondrion is considered to behave independently.

The result of this 'discrete' distribution is that the 'natural world' can be modelled
with 'uncommon events occurring uncommonly' and 'uncommon events following uncommon events', albeit rarely.
And, this process can lead to the establishment of a new mutation occurring in mitochondrial DNA
over a number of generations. The model also shows that the majority of mutations fail to become established.

Although this model has be written to demonstrate mutation behaviour for Family History purposes,
it also shows how a pathological mutation, such as might cause a myopathy, can become established.
In this situation an increasing 'mutation load' in the cell population for muscle can lead to a disease
which is worse in the children than in the parents.