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Do chickens really take on “dinosaurian traits” inside the egg as one paleontologist claims? Dr. Elizabeth Mitchell, AiG–U.S., shows why there’s more fluff to this claim than fact.
We recently received the following request:
I quote from The Reader’s Digest August, 2010 article “Jurassic Spark” where paleontologist Hans Larsson states “Chicken embryos...start off looking fairly generic...As the embryo continues to transform, there’s a brief window when . . . it takes on dinosaurian traits. For a mere ten hours, the chicken embryo has five fingers with pointed and claw-like tips, a hint of teeth and a tail (up to 22 vertebrae, roughly 15 more than in a developed chicken). Then suddenly, a genetic switch flips: The teeth disappear, the tail is destroyed and the five fingers become three.”
How would you respond to this?
The article in Reader’s Digest (Canadian edition) came from a Macleans article entitled “The Quest to Build a Dinosaur.”
Reading this article is very entertaining—if you like science fiction—and discussing it with your friends should provide countless opportunities to draw a line between reality and fantasy. Paleontologists Jack Horner—advisor on the Jurassic Park movies—and Hans Larsson are, however, quite serious when they talk about their efforts to genetically alter chicken embryos to turn them into dinosaurs. Why do they wish to do this? As Horner states, “You can’t make a dinosaur out of a chicken, if evolution doesn’t work.” In other words, they would like to “spark . . . a public debate about evolution by winding its tape backwards for all to see.”
Horner is strongly committed to the notion that dinosaurs evolved into birds. As Dr. Tommy Mitchell points out in his presentation called Jurassic Prank, Horner, in the “Special Features” section of the Jurassic Park DVD, states:
The whole idea is to get people to look at dinosaurs more like birds than reptiles. In one of the scenes, some of the model makers had made a tongue come out like a lizard or a snake . . . . We know they didn’t do that. Had that been left in the scene, all that work into making these things birdlike would have been gone.
Unlike the characters in the movie, real scientists do not have any dinosaur DNA. (None of the dinosaur soft tissues found by Mary Schweitzer have provided any DNA.) With no dinosaur DNA, they have nothing to clone. Instead, Larsson and Horner are trying to alter the development of chicken embryos in hopes of producing mutant chickens with tails, forearms, and teeth. They admit, however, that even if they could get something like this to happen, the creature would “still have a chicken genome.”1 In other words, it would not be a dinosaur, just a funny looking chicken. (Larsson would disagree, however, since he says, “Chickens are dinosaurs.”)
Notice that even with induced mutations thought to mimic evolutionary ones, these scientists acknowledge that their creation would not be a dinosaur because it would not contain dinosaur DNA. Mutations do not create new information; they just reshuffle, misplace, turn on or off, or lose information that is already there. Evolution of one kind of animal into another kind would require new information to be created.
In a sadly accurate comparison, the article recalls the tragedy of thalidomide, a teratogenic (birth-defect causing) drug given to treat morning sickness in Europe in the 1960s. These children were fully human and suffered from a variety of problems, including blunted development of the limbs. (This congenital malformation is called phocomelia, a name coined from Greek words that describe the resemblance of the limbs to the flippers of a seal.)
Thalidomide is thought to have caused these defects by inserting itself into the DNA of the developing baby and preventing certain genes related to limb development from being activated. The article notes that this mutation had “nothing to do with development or evolution,” even though these children had “flipper-like hands and feet.” In fact, this mutation had nothing to do with evolution because these children were still fully human. But, actually, the mutation caused by thalidomide in many ways resembles the process Larsson and Horner are trying to trigger: the turning off or on of certain genes. And just as thalidomide babies were still human babies, a mutant chicken is still a chicken.
Some biology textbooks continue to present the recapitulation myth as evidence for evolution.Disturbingly, in this article, a concept that should now be as extinct as the dinosaurs rises from Ernst Haekel’s grave. The notion that “ontogeny recapitulates phylogeny”—an idea held by both Darwin and Haekel—presumed that the developmental stages of an embryo retrace its evolutionary past.2 In spite of the fact that Haekel’s diagrams were known to be frauds almost immediately after they were published,3 some biology textbooks continue to present the recapitulation myth as evidence for evolution.4 Relying on embryonic recapitulation, Larsson attempts to stop the chicken embryo from losing its so-called dinosaur characteristics. He says that for 10 hours the chicken embryo has “dinosaurian traits,” and he is trying to “override” the genetic mandate the creature has to lose these traits and become a bird.
One of these “dinosaurian traits” is a tail, or rather, to be more accurate, a tail-bud that resembles a tail.5 Paleontologist Larsson claims that the chicken embryo briefly possesses “a tail (up to 22 vertebrae, roughly 15 more than in a developed chicken).”6 This statement is misleading. As embryos develop, they form a series of somites. Somites are blocks of embryonic tissue genetically programmed to develop into specific tissues (such as muscle, skin, and bone) and to direct the organization of other nearby structures such as nerves. The disappearance of these “extra” somites in chick embryos involves a combination of transformation into other structures, migration to other locations, and some genetically programmed cell death.
Research has suggested that the genetically programmed death of the cells in some of these somites (a process called apoptosis) serves to regulate the development of neighboring structures.7 But even if these “genetic switches” could be disabled, the resulting malformations would result in defective chickens, not dinosaurs.
The hope of these scientists—to switch on the dinosaur genes and switch off the chicken genes—depends on the notion that the dinosaur information is actually there in the chicken genome but just deactivated (never mind the question of where that genetic information came from in the first place). One scientist in the article states, “Evolution doesn’t always rely on the development of new genes. It’s redeploying old genes in new ways: changing their switches, or their time of activity.”
In other words, the claim that “most creatures share many of the same genes,” coupled with the discovery of “homeobox” genes in fruit flies, genes that can switch on or off the development of body parts in certain places,8 is used to imply that the genetic information is the same for most things anyway and only has to be switched on or off to evolve a new kind. The article hastens to remind us of the claim that human and chimp DNA is “about 99 percent identical.” Statistically speaking, that number is not very accurate. The way some information is counted and other informational differences are ignored artificially inflates that percentage. Moreover, using percentages hides an important fact: “If 5% of the DNA is different, this amounts to 150,000,000 DNA base pairs that are different between them!”9
Clearly, there are many proteins and other molecules that show up in multiple creatures. Therefore, it is not surprising to find that the DNA blueprints to make these chemicals appear to be “cut-and-pasted” throughout the living creatures of the world. But why should this come as a surprise? Did not the same Creator, according to the Bible, create all these living creatures? Is there some reason we should have expected that God ought to have invented a whole different kind of biochemistry for each and every creature?
If we, as mere human beings, can use the same inventions in multiple places and for multiple uses, should it surprise us that God used His good ideas in a variety of places? When we see common designs, or common components, our own worldview determines whether we shout “common Designer” or “common ancestor.”
After pointing out that some DNA from other extinct species has been recovered, such as the DNA from the hair of the wooly mammoth, the article explores the possibility of cloning. Here the article raises a hypothetical but disturbing ethical issue: if a Neanderthal could be cloned from DNA—presumably without all the horrid problems10 inherent in the reproductive cloning process as revealed by Dolly11—what would its moral status be? Now, the fact is, Neanderthals were as human as you or I.12 However, this article asks whether this “sibling species” would be kept “in a zoo . . . treated as a low-functioning human . . . . Would it be closer to an ape, or to a person?” Knowing the tragic story of Ota Benga, an African pygmy displayed in a zoo because he was thought to occupy an inferior position on the evolutionary ladder, these hypothetical questions have a frightening ring.
Maybe this article isn’t so entertaining after all.
Elizabeth Mitchell, MD