Genome complexity: a review of Reznick's guppies II (Introduction)

by David Turell , Thursday, May 09, 2024, 20:06 (11 days ago) @ David Turell

Next paper;

https://evolutionnews.org/2024/05/predictions-for-the-guppy-from-the-engineering-design...

"One hypothesis involves preservation of genetic diversity amongst the population, where diversity means that individuals within a population represent different optimizations for unique environments. Think of this scenario as a normal distribution where certain individuals in the population, who are not well suited for one environment (i.e., downstream), could thrive if placed in a different location (i.e., upstream) and gradually their alleles would become dominant in that environment.

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"A second hypothesis is that there is a sensing mechanism, which in response to detected environmental inputs would trigger germline reprogramming. This relies on organisms sensing changes in the environment and triggering internal programming of allele frequency in the next generation, rather than natural selection (NS) based on standing genetic variation being the source of change. While a fully described mechanism of this nature has yet to be identified in living systems, there is some evidence supporting this hypothesis.

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"Additionally, a recent study found substantial differences in germline mutation rates among three separate guppy families. These de novo mutations were shared among many siblings, indicating they occurred early in embryonic development. These findings are consistent with certain individuals within a population being programmed for adaptation, while others are not.

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"What Separates Design/Engineering from Darwinian Macroevolution?
Some unique aspects which separate the design/engineering model from the evolutionary one are:

"Adaption is expected to be tightly regulated, targeted, and sometimes reversible, just like human-engineered tracking systems. Because of these features, adaptation is expected to be predictable.

"The organism, not the environment, exerts control over its adaptation.
The design of the organism determines what environmental stimuli the organism tracks and responds to.

"Environments do not possess agent-like capabilities of “selecting” which organisms will breed. The traits of organisms themselves are responsible.

"Organisms are problem-solving entities not passive objects being shaped by the environment.
Organism operational parameters have a limited range.

"Expanding that last point, for the guppy and all the other listed examples, the main design architecture of the organism remains unchanged despite the fact that a trait’s variability can be adjusted for optimum performance. The guppy can change and adapt like a well-engineered system, but at the end of the day, it is still a guppy."

Comment: a very different view of adaptability controlled by specific mechanisms in the DNA. It follows Shapiro's thinking. A designer could well have arranged this system. It is still within the species, not speciation.