Darwin dissed? no, defended by Darwinist authors (Introduction)

by David Turell @, Saturday, February 24, 2018, 18:29 (2253 days ago) @ David Turell

An interesting defense of Dawkins selfish genes, by making assumptions against the presented evidence that 80% of DNA has some functions:

https://aeon.co/essays/our-genome-is-not-a-blueprint-for-making-humans-at-all?utm_sourc...

"Our genome has more than 20,000 genes, relatively stable stretches of DNA transmitted largely unchanged between generations. These genes contain recipes for molecules, especially proteins, that are the main building blocks and molecular machines of our bodies. Yet DNA that codes for such known structures accounts for just over 3 per cent of our genome. What about the other 97 per cent? With the publication of the first draft of the human genome in 2001, that shadow world came into focus. It emerged that roughly half our DNA consisted of ‘repeats’, long stretches of letters sometimes found in millions of copies at seemingly random places throughout the genome. Were all these repeats just junk?

***

"After working hard for almost a decade, in 2012 ENCODE came to a surprising conclusion: rather than being composed mostly of useless junk, 80 per cent of the human genome is in fact functional.

"To reach that conclusion, ENCODE systematically scouted the genome as a whole for specific functions. One function could be coding for proteins; another function could be acting as a ‘molecular switch’ that regulates the operation of other genes. In one experiment, for example, ENCODE surveyed the entire genome for DNA that is bound by ‘transcription factors’ - proteins known for calling other genes into action. In this way, ENCODE compiled a comprehensive and very useful catalogue that provided a functional clue for 80 per cent of the 3 billion nucleotides that comprise all the genes of the human genome.

***

"Consider the so-called ‘LINE-1 elements’, a DNA sequence formerly classed as junk. Our genome teems with 500,000 copies of this 6,000-letter sequence that seems to do nothing but reproduce copies of itself, the very definition of the ‘selfish gene’. According to ENCODE, these LINE-1 elements are functional since they are biochemically active. But does this mean they function to further human survival itself?

"Likely not. ‘Function’ is a loaded word, and ENCODE chose a very inclusive definition: in the ENCODE world, function can be ascribed to any stretch of the genome that is related to a specific biochemical activity.

***

"Indeed, many of ENCODE’s 80 per cent ‘functional elements’ are unlikely to contribute to human survival and the reproduction of human genomes, which is what you would expect if you consider function from the perspective of a human blueprint.

"Yet viewing our genome as an elegant and tidy blueprint for building humans misses a crucial fact: our genome does not exist to serve us humans at all. Instead, we exist to serve our genome, a collection of genes that have been surviving from time immemorial, skipping down the generations. These genes have evolved to build human ‘survival machines’, programmed as tools to make additional copies of the genes (by producing more humans who carry them in their genomes). From the cold-hearted view of biological reality, we exist only to ensure the survival of these travellers in our genomes.

"This is the central idea in Richard Dawkins’s milestone book, The Selfish Gene (1976), and the fundamental shift in perspective it entails might be as hard to accept as it was hard to acknowledge that our world revolves around the sun, not the sun around us. The selfish gene metaphor remains the single most relevant metaphor about our genome.

***

"At the most fundamental level, then, our genome is not a blueprint for making humans at all. Instead, it is a set of genes that seek to replicate themselves, making and using humans as their agents. Our genome does of course contain a human blueprint – but building us is just one of the things our genome does, just one of the strategies used by the genes to stay alive.

***

"ENCODE has called 80 per cent of the human genome functional, yet 97 per cent of the genome does not encode proteins or other molecules that support human life. Is all this DNA just junk? Of course not. There are undoubtedly many molecules whose function we have not yet grasped. And a blueprint alone is not enough to build anything – you also need assembly instructions and a time plan that orchestrates the building process. The portion of the genome responsible for this organisational feat likely adds another 7 per cent or so to the blueprint’s 3 per cent, leading scientists to suspect that about 10 per cent of the genome is actually needed to specify a functioning human." (my bold)

Comment: There are many essays trashing this line of reasoning. We have no idea to make a living organism. All we know is DNA makes proteins. Note my bold. Seven to ten percent to make life is a ridiculous assumption. The essay describes two sets of scientists squabbling. I'm with ENCODE.


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