Tuesday, September 7, 2010

The humble truth of genes (3)

Some readers may be already arguing that
there are situations where a child is born defective (e.g. Down Syndrome)
and that could seriously prove impossible to treat/prevent,
despite the change of diet, living environment, exercise etc...

This is very true.
But these events are rare and
are usually due to some 'ad hoc' malicious mutations or deletion in gene coding.
This is the only situtation where genes could be 'blamed'
(still it is arguable, because the parents, with sufficient information and education, could avoid these mutations sometimes).

Most common degenerative diseases like
diabetes typeII, cardiovascular diseases, adulthood cancers, allergy etc
that contribute bulk of the death in modern days,
are not due to malicious mutations or deletion in gene coding.

In some of these degenerative diseases,
genes may play a slightly bigger part.
E.g. some women are more susceptible to Breast Cancer
if they inherit certain variant forms of BRCA1 from their ancestors.
But still, genetic predisposition isn't everything.

Another important concept about genes stemming from this discussion is that
there is actually no gene that is meant for causing cancer or
making one susceptible to cancer (or any disease).

During the course of evolution (over hundreds/thousands of years),
genetic codes randomly and gradually vary (a kind of natural mutation).
Sometimes the variation will improve the function of a gene
sometimes it is the reverse.

When a genetic code changes to one that compromise the function of the gene,
the new species is naturally selected against (in term of bioogical/social survival and offspring propagation).
So, eventually there is no truly bad variant that gets carried onto the next generation.

In the case of cancer susceptible BRCA1 variants,
they were not meant to cause cancer despite their compromised functions (in DNA repair).
If these cancer susceptible BRCA1 variants were truly bad,
they won't have been passed on from their ancestors
-- because their far end ancestors bearing these variants would have been compromised in their survival/reproduction.

The real situation is that these cancer susceptible variants
could not cause cancer given the environment, diet and lifestyle during their ancestors' time.

When the era changes,
the environment changes (now with more pollution),
the diet pattern changes (now with a lot more meat and food chemicals),
the lifestyle changes (now with less exercise opportunity and more stress),
certain BRCA1 variants could not handle so much 'workload'
and hence now labelled cancer susceptible variants.

The whole issue is very clear,
in order to prevent breast cancer(or a disease),
one can choose
to blame on their misfortune to have inherited the susceptible variants
(where nothing more could be done)
to create an environment, diet pattern, lifestyle that mimic the ancestral time
when these nowadays-so-called susceptible variants were totally harmless.

Question may arise:
How is it possible now to live like our ancestors?
-- exactly a question reflecting one's unwillingness to change and to step out of their comfort zones
as indicated in previous post :P

Kee Yew

{Learning Holistic Wellness for Wisdom and Compassion}

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