Posted on 05/24/2007 10:47:48 AM PDT by SubGeniusX
WASHINGTON (Reuters) - Primitive fish already may have possessed the genetic wiring needed to grow hands and feet well before the appearance of the first animals with limbs roughly 365 million years ago, scientists said on Wednesday.
University of Chicago researchers were seeking clues behind a momentous milestone in the evolution of life on Earth -- when four-legged amphibians that descended from fish first colonized dry land. These first amphibians paved the way for reptiles, birds and mammals, including people.
"What we're interested in here is the transition from fin to limb -- a great evolutionary event," palaeontologist Neil Shubin, an author of the research with colleagues Marcus Davis and Randall Dahn, said in a telephone interview.
They studied one of the most primitive types of fish on Earth -- the long-snouted paddlefish Polyodon spathula -- and found the fish that predated the first land vertebrates may have possessed genetic underpinnings for limb development.
"What we found is that aspects of the genetic program and the patterns of gene activity that serve to make hands and feet are actually found in the fins of fish -- not just any fish but in primitive living fish," Shubin added.
The research was published in the journal Nature.
Paddlefish, found in freshwater locales in the United States and China, are early "ray-finned" fish. Their fleshy fins are structurally similar to fish predating the first land creatures. Their fins contain cartilage thought to correspond to the upper arm bone of land vertebrates, Shubin said.
While paddlefish are ancient, they did not exist at the time of the vertebrate conquest of land, but are seen as an evolutionary offshoot of some fish around at that time.
GENE PATTERNS
The researchers looked at so-called Hox genes -- which play an important role in limb development -- in paddlefish pectoral fins. They inserted molecular markers to track where these genes are active in the fin, and found the activity pattern resembled what these genes do in limbs of land dwellers.
The findings run counter to the theory that the appearance of limbs was a novel evolutionary occurrence requiring great genetic changes to enable the first limbed creatures to adapt to their new environments of streams and swamps.
The first forests sprouted up roughly 385 million years ago, with towering trees resembling modern-day palms, helping give rise to new freshwater ecosystems.
Shubin and other scientists last year announced the discovery of the remains of a creature called Tiktaalik dating back to 375 million years ago and seen as a missing evolutionary link between fish and the first land vertebrates.
It had fish-like characteristics, but it boasted a skull, neck, ribs and parts of limbs resembling the first amphibians such as Acanthostega that arose 5 to 10 million years later.
"So it seems like you had the genetic tool kit (for limbs) for a long period of time," Shubin said. "And then, when the new ecosystems appear at around the time of Tiktaalik and slightly before, that's when forms started to use that to make true fingers and toes and stuff like that."
...but their final assembly was handled by Airbus...
Ping
Just goes to show that the curse of the Democrats goes back a long ways.....
;-)
Yeah. The fossil of where the fin was turning to a limb . . the elusive fossil. Also, fish DNA turning into human DNA . . fossil evidence of that is also elusive . . .
if they wanted to...
But G-d said stick to the water ...
Oops forgot the /sarc
better now ....
Big “C” Creation through evolution, with the Lord’s plan built in from the start.
What you talkin' 'bout?.......
I still think liberals still have the precursors of brains.........
You have any evidence for that claim?
Anecdotal evidence only........
Anecdotes could be caused by finding some precursors for conservatives & mistaking them for liberals.
It’s all in the code. There would be a lot more functions and structural features that have not yet developed and might never.
“The researchers looked at so-called Hox genes — which play an important role in limb development — in paddlefish pectoral fins. They inserted molecular markers to track where these genes are active in the fin, and found the activity pattern resembled what these genes do in limbs of land dwellers.”
Even I, with half my brain tied behind my back, can understand that this is not about an alleged gene for limbs.
By the way, the term “genetic wiring” is deliberately chosen so as to obfuscate. There is no such thing as “genetic wiring”.
Another example of a scientist rushing to the microphone before knowing the script, and a too-eager media ready to confuse the public.
genetic program = source code
patterns of gene activity = data arrays and/or the application itself
An ancestor of this fish, decided on it's own that it needed to modify it's internal genetic program such that one day, several million years later, it's great-great...grand child fish would then use this modified code to grow arms from fins so that it can crawl onto land and start living a better life, an easier life, a life of purpose.
Fortunately for it, it was pregnant at the time and it's swamp born babies got arms and not fins. Now add trillions of self generated code modifications, plus 400 million years and you get humans. And now you know the rest of the story.
Like the fossils mentioned here?
[wipes tears from eyes]
...some fish......
[Bursts into uncontrollable laughter again]
It’s part of the design.
;-)
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