Darwinism Evolution Intelligent Design

Researchers: Darwin’s finches not typical example of evolution at all

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Researchers: This system is exceptional in terms of the rates of evolutionary change and adaptive divergence, and it is likely that this may be due to the uncommon circumstances posed by the isolated and fragmented Galápagos landscape.

At Molecular Ecology:

Abstract: Beak shape in Darwin’s ground finches (Geospiza) is emblematic of natural selection and adaptive radiation, yet our understanding of the genetic basis of beak shape variation, and thus the genetic target of natural selection, is still evolving. Here we reveal the genomic architecture of beak shape variation using genomewide comparisons of four closely related and hybridizing species across 13 islands subject to parallel natural selection. Pairwise contrasts among species were used to identify a large number of genomic loci that are consistently related to species differences across a complex landscape. These loci are associated with hundreds of genes that have enriched GO categories significantly associated with development. One genomic region of particular interest is a section of Chromosome 1A with many candidate genes and increased linkage. The distinct, pointed beak shape of the cactus finch is linked to an excess of intermediate frequency alleles and increased heterozygosity in significant SNPs, but not across the rest of the genome. Alleles associated with pointier beaks among species were associated with pointier-beaked populations within each species, thus establishing a common basis for natural selection, species divergence and adaptive radiation. The adaptive genomic landscape for Darwin’s finches mirrors theoretical expectations based on morphological variation. The implication that a large number of genes are actively maintained to facilitate beak variation across parallel populations with documented interspecies admixture challenges our understanding of evolutionary processes in the wild. (paywall) – Lawson LP, Petren K. The adaptive genomic landscape of beak morphology in Darwin’s finches. Mol Ecol. 2017;00:1–12. https://doi.org/10.1111/mec.14166 More.

Final paragraph:

In Darwin’s finches, hundreds of loci appear to be involved in maintaining distinct phenotypic differences between species, and these loci are highly associated with developmental genes. This number of loci poses several challenges for advancing our understanding of evolutionary processes. First, further functional verification of the role played by each of hundreds of implicated genes poses a large obstacle using traditional mis-expression techniques. Beginning by validating those genes in common between MLM, GLM and Fst analyses before proceeding to the entire data set may help prioritize the most likely candidates for craniofacial change. Second, how so many genetic differences can become co-aligned over time in the face of ongoing gene exchange challenges our understanding of evolutionary processes. This system is exceptional in terms of the rates of evolutionary change and adaptive divergence, and it is likely that this may be due to the uncommon circumstances posed by the isolated and fragmented Galápagos landscape.

So the textbook Darwin’s finches, revered icons of textbook evolution, are not a good example? Never mind. They’ll still be in the books a decade from now anyway.  As Zombie Science  shows, these icons just keep coming back.

See also: Darwin’s finches not a good example of Darwinian evolution, but of hybridization

 

5 Replies to “Researchers: Darwin’s finches not typical example of evolution at all

  1. 1
    Dionisio says:

    “{…] our understanding of the genetic basis of beak shape variation, and thus the genetic target of natural selection, is still evolving.”

    yes, they’re correct, their [mis]understanding of the whole biology enchilada keeps changing because they are not open-minded, they keep thinking within wrongly preconceived boxes, they do reductionist bottom-up reverse engineering of marvelous biological systems that were top-down designed.
    That’s why they often write “surprisingly”, “unexpectedly”, and things like that.
    However, they ain’t seen nothin’ yet.
    The most fascinating discoveries are still ahead.
    They better fasten their seatbelts before they get to the more thrilling part of the ride.
    So yes, I agree with them in that the archaic pseudoscientific hogwash (low grade bovine excreta) they keep thinking of seems to evolve (somehow).
    Oh, well… what else is new?
    🙂

  2. 2
    vmahuna says:

    Oh, I hadn’t thought about the real problem being Bottom-Up analysis. Bottom-Up NEVER works, but LOTS of people (computer programmers, over-specialized specialists, managers who only ever understood 1 part of the business…) DEMAND the analysis be done Bottom-Up.

    Object-Oriented whatever the O-O guys thought they were doing wasted TONS of money. And the best you could hope for was 1 or 2 low level functions that fit in SOMEPLACE. The rest of the crap never fit at all, because Bottom-Up never bothers to identify what the TOP of the process is. The truly amazing thing about software development is you really can achieve 100% complete total failure write-offs: absolutely NOTHING is salvageable.

    But the programmers thought it was fun and NOBODY in management had ANY idea what they were actually doing, project completion-wise.

  3. 3
    Dionisio says:

    vmahuna,
    That’s an interesting observation. Thanks for sharing your experience in that field.
    I worked on a project that existed in my technical director’s mind long before his team started to work on it.
    Definitely top-down design. It was a success.

  4. 4
    Dionisio says:

    The OP for this thread has a very interesting title but apparently it did not attract any politely dissenting commenter.
    Perhaps they lack what is required to comment on this? Maybe they ran out of valid arguments, assuming they ever had any. 🙂

  5. 5
    Dionisio says:

    At the end of the day they have to present macro evolutionary cases that satisfy the basic evo-devo conditions described @1090 in the thread “A third way of evolution?”.

    The Darwinian evo-devo folks have written gazillion papers but still the main question one asks after reading them is: where’s the beef? 🙂

    The Darwinian researchers will remain surprised by unexpected discoveries as long as they keep their reductionist bottom-up reverse engineering approach to biology.

    The Darwinian researchers will remain ‘surprised’ by ‘unexpected’ discoveries as long as they reject open-mindedness and refrain from thinking out of wrongly preconceived boxes.

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