Saturday, January 7, 2017
The Amazing Reality of Genetic Life
The amazing, incredible reality of genetic life...
If I got to live, again, and was born with scientific ability, it would be difficult
for me to choose between the fields of astrophysics/astronomy
Genetics is a fascinating field of endeavor which has greatly altered how thinkers view Life and reality.
Consider this measured reflection from a science website:
"One of the surprises that came out of the Human Genome Project was how few genes (protein coding stretches of DNA) humans
have — around 23,000,
not that different compared to the fruit fly with 14,000,
and quite a bit less than rice, with 51,000."
So we human beings, homo sapiens, are situated between
a fruit fly
and a grain of rice!
We have more genes than a fruit fly, but less than a grain of rice!
Sounds hilariously bizarre, like some sort of slapstick movie comedy.
What sense does all of this make?
"Traditionally the metaphor for genes was something more akin
to a blueprint, — the “standard dogma” of Francis Crick: each gene codes for
one mRNA which codes for one protein — but now we realize that many are better viewed as switches or volume knobs.
Moreover, one gene can have multiple effects. Complexity arises not so much from
the genes themselves as from the connections between them.
These network properties are currently an enormously rich topic of research. For example, the way the network is connected can dramatically affect the interplay between robustness to mutation and evolvability (the ability of a system to generate heritable phenotypic novelty).
The same gene often turns out to be used throughout the animal kingdom:
you can take the pax-6 gene that controls eye development from a human and put
it into the part of a fly that controls wings formation and the fly will make a (malformed) eye on its wing.
The same gene that controls the formation of human arms also controls the formation
of wings on birds, fins on fish, and legs on centipedes!
Modifying the way these genes are “wired together” can lead to massive changes
in an organism.
The burgeoning new field of evodevo (evolutionary developmental biology) studies how evolution exploits these “toolbox genes”
to help generate the endless forms most beautiful we see around us.
Much remains to be understood, but adjectives
like remarkable, elegant, and awe-inspiring are apt.
Clay or Lego blocks?
In a fascinating book proposing a “theory of facilitated variation” biologists Marc Kirschner and John Gehrard point out that while
the Modern Synthesis implicitly used the metaphor of clay -- evolution could produce variation in almost any direction,
but in very tiny steps--
modern biology would be better served by the metaphor of Lego blocks:
reusable connectable units are more constrained in what they can do, but you can generate useful new variation in much larger steps.
Selfish genes, or control on many levels? The field of systems biology is challenging
the reductionist bottom-up primacy that has dominated biological explanation over the last few decades.
In a beautiful book, The Music of Life: Biology beyond the Genome (OUP 2006),
Denis Noble, a remarkable polymath and one of the fathers of systems biology, takes the gene-centric view of his Oxford colleague Richard Dawkins to task.
He asserts that we must look beyond the “selfish gene."
A better metaphor for understanding life is music, “a symphonic interplay between genes, cells, organs, body, and environment."
from the BioLogos Website
On the reality of evolution--
"One way to view the dogmatic nature of neo-darwinism as it is often presented in public is to see it as a reaction to the dogmatism of the creationists. The ‘uncertain’ (in the sense of lacking reason) faith in creationism is replaced by the ‘certainties’ of science.
But there is a conflation here of very different degrees of certainty in science. There can’t be much doubt about the fact that life on earth has evolved.
There is much less certainty about the mechanisms. Unlike Darwinism (Darwin knew nothing of mechanisms, genes were not known), neo-darwinism proposes the exclusion of many mechanisms that have in fact now been found to occur in nature.
Adopting the ‘certainty’ of evolution to clothe the ‘uncertainty’ of particular theories about mechanisms has been the cause of many problems in public debate on evolution.
It is perfectly possible to defend the virtual certainty that life has evolved while debating in the usual argumentative scientific way the uncertainties surrounding the question of mechanisms.
The truth is that amongst the many mechanisms now known we know very little about which were prevalent in evolution. The answer is likely to be that different mechanisms were dominant at different stages.
Evolution itself evolves."
By biologist and evolutionist Denis Noble
from Wikipedia: "Denis Noble is a British biologist who held the Burdon Sanderson Chair of Cardiovascular Physiology at the University of Oxford from 1984 to 2004... He is one of the pioneers of Systems Biology and developed the first viable mathematical model of the working heart in 1960."
How amazing, incredible, and wonderful is Life and Reality!
In the Light,