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When evolution ran backwards?

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Pacific hagfish Myxine.jpg
Pacific hagfish

From Jenny Morber at National Geographic, a look at five examples of “regressive evolution,” including:

Now, in a shock to biologists, a close look at a 300-million-year-old hagfish fossil reveals that the [now blind] animals once had working eyes—and evolution took them away.

The discovery challenges the way scientists think about the origins of the eye. Living hagfish are remarkably unchanged from their ancient counterparts, and so scientists long thought that modern, sightless hagfish eyes represented a kind of intermediate step between the primitive light-sensing spots in many invertebrates and the camera-like eyes of vertebrates, including humans. More.

Not so, apparently. Stranger still is the fact that selective breeding of different populations of blind cave fish enabled sight to be restored in some offspring because the losses involved different genes. And, as Morber reports, researchers have tweaked chicken embryos to the point of giving them the beginnings of teeth.

Morber closes, “No matter why birds lost their teeth, several lines of research suggest that it did not take much genetic change to make the switch.” No, but in this case, reversing it required purposeful action resulting from knowledge and intelligence.

The loss process is also called ”devolution” and is easier to spot in parasites, where it is much more rampant.

See also: Devolution: Getting back to the simple life

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One Reply to “When evolution ran backwards?

  1. 1
    bornagain77 says:

    OT:

    Dolphin DNA very close to human, – 2010
    Excerpt: They’re closer to us than cows, horses, or pigs, despite the fact that they live in the water.,,,
    “The extent of the genetic similarity came as a real surprise to us,” ,,,
    “Dolphins are marine mammals that swim in the ocean and it was astonishing to learn that we had more in common with the dolphin than with land mammals,” says geneticist Horst Hameister.,,,
    “We started looking at these and it became very obvious to us that every human chromosome had a corollary chromosome in the dolphin,” Busbee said. “We’ve found that the dolphin genome and the human genome basically are the same. It’s just that there’s a few chromosomal rearrangements that have changed the way the genetic material is put together.”
    http://www.reefrelieffounders......-to-human/
    Kolber, J., 2010, Dolphin DNA very close to human, viewed 18th March 2012,
    Kumar, S., 2010, Human genes closer to dolphin’s than any land animal, Discovery Channel Online,
    http://biol1020-2012-1.blogspo.....nomes.html

    and:

    On Human Origins: Is Our Genome Full of Junk DNA? Pt 2. – Richard Sternberg PhD. Evolutionary Biology – podcast
    Excerpt: “Here’s the interesting thing, when you look at the protein coding sequences that you have in your cell what you find is that they are nearly identical to the protein coding sequences of a dog, of a carp, of a fruit fly, of a nematode. They are virtually the same and they are interchangeable. You can knock out a gene that encodes a protein for an inner ear bone in say a mouse. This has been done. And then you can take a protein that is similar to it but from a fruit fly. And fruit flies aren’t vertebrates and they certainly are not mammals., so they don’t have inner ear bones. And you can plug that gene in and guess what happens? The offspring of the mouse will have a perfectly normal inner ear bone. So you can swap out all these files. I mentioning this to you because when you hear about we are 99% similar (to chimps) it is almost all referring to those protein coding regions. When you start looking, and you start comparing different mammals. Dolphins, aardvarks, elephants, manatees, humans, chimpanzees,, it doesn’t really matter. What you find is that the protein coding sequences are very well conserved, and there is also a lot of the DNA that is not protein coding that is also highly conserved. But when you look at the chromosomes and those banding patterns, those bar codes, (mentioned at the beginning of the talk), its akin to going into the grocery store. You see a bunch of black and white lines right? You’ve seen one bar code you’ve seen them all. But those bar codes are not the same.,, Here’s an example, aardvark and human chromosomes. They look very similar at the DNA level when you take small snippets of them. (Yet) When you look at how they are arranged in a linear pattern along the chromosome they turn out to be very distinct (from one another). So when you get to the folder and the super-folder and the higher order level, that’s when you find these striking differences. And here is another example. They are now sequencing the nuclear DNA of the Atlantic bottle-nose dolphin. And when they started initially sequencing the DNA, the first thing they realized is that basically the Dolphin genome is almost wholly identical to the human genome. That is, there are a few chromosome rearrangements here and there, you line the sequences up and they fit very well. Yet no one would argue, based on a statement like that, that bottle-nose dolphins are closely related to us. Our sister species if you will. No one would presume to do that. So you would have to layer in some other presumption. But here is the point. You will see these statements throughout the literature of how common things are.,,, (Parts lists are very similar, but how the parts are used is where you will find tremendous differences)
    http://www.discovery.org/multi.....-dna-pt-2/

    Kangaroo genes close to humans
    Excerpt: Australia’s kangaroos are genetically similar to humans,,, “There are a few differences, we have a few more of this, a few less of that, but they are the same genes and a lot of them are in the same order,” ,,,”We thought they’d be completely scrambled, but they’re not. There is great chunks of the human genome which is sitting right there in the kangaroo genome,”
    http://www.reuters.com/article.....P020081118

    Darwinism Versus the Octopus: An Evolutionary Dilemma – Eric Metaxas – September 08, 2015
    Excerpt: What’s the difference between evolutionary theory and an octopus? Well, one is a slippery, color-changing escape artist that can get out of any tough situation and the other is an aquatic invertebrate.,,,
    The key to this uncanny intelligence is the octopus’ so-called “alien” nervous system, brain, and eyes. But these features are not alien to the animal kingdom at all. In fact, they’re quite common in higher vertebrates. The octopus genome shares key similarities with ours, including the development of high-powered brains and “camera eyes” with a cornea, lens, and retina.
    Now here’s the problem for evolution: according to Neo-Darwinists, we’re not related to octopi—at least not within the last several hundred million years. That means all of these genes, complex structures, and incredible capabilities came about twice.
    The researchers who sequenced the octopus genome call this “a striking example of convergent evolution,” or the supposed tendency of unrelated creatures to develop the same traits in response to environmental pressures. Isn’t that just a fancy way of saying a miracle happened twice?
    But the octopus isn’t the only such miracle. “Convergent evolution” is all over nature, from powered flight evolving three times to each continent having its own version of the anteater. Think about that. As one delightfully un-self-conscious “Science Today” cover put it, convergent evolution is “nature discover[ing] the same design over and over.” Well, good for nature!
    But as Luskin argues, there’s a better explanation for a tentacled mollusk having a mammal’s brain and human eyes. And that explanation is common design by an intelligent Engineer. And like all good engineers, this this one reused some of His best designs.
    Now that explanation isn’t going to satisfy Darwinian naturalists. And they’ll probably keep on invoking “convergent evolution” when faced with impossible coincidences in nature.
    But hopefully knowing a more straightforward explanation leaves you forearmed—or should I said “eight-armed”?
    http://www.christianheadlines......lemma.html

    The octopus genome and the evolution of cephalopod neural and morphological novelties – August 13, 2015
    Excerpt: the independent expansions and nervous system enrichment of protocadherins in coleoid cephalopods and vertebrates offers a striking example of convergent evolution between these clades at the molecular level.
    http://www.nature.com/nature/j.....14668.html

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