Chicken teeth



In 2006, scientists researching the effects of a recessive talpid2 gene in chicks discovered small protrusions that revealed the genetic ability to grow teeth in birds. Though many evolutionary scientists cite this study as a momentous victory for the theory of evolution, Creationists too refer to the findings as additional insight into the original creation.

History
In 2006, developmental biologist Matthew Harris was continuing research into the talpid2 gene in chickens, a recessive gene that results in the death of the chicken before hatching. While examining a 16-day old chicken embryo's beak that carried the gene one night, Harris made the startling discovery of teeth-like projections coming from the edges of the beak. Small, saber-shaped, and conical, these protuberances do not appear in chickens that do not carry the talpid2 gene, which make up the vast majority of modern chickens. In further studies, scientists noted that the same two tissue layers that produce teeth in mammals came together in the mutant chicken embryos to produce these nascent teeth. In vertebrates, a gene known as sonic hedgehog (shh) remains essential to tooth production. In normal chickens, this gene is expressed in an area analogous to the sides of the gums, but in mutant chicks and alligators, this gene is expressed analogous to the middle of the gums. Essentially, the talpid2 gene altered the chickens genome to “turn on” the existing gene for teeth. Matthew Harris and biologist John Fallon, working with the same talpid2 genes, later engineered a virus that mimics the chemical signals of the mutation and exposed the virus to healthy chickens. The virus caused small teeth to burgeon on the beak that were quickly reabsorbed.

Many scientists first pointed to the evolutionary implications of these findings. The modern theory of evolution asserts that modern birds evolved from reptiles not unlike dinosaurs roughly 70-80 million years ago. Therefore, the fact that these chickens possess the genetic potential to grow teeth offered further validation to this theory. Apparently, the genes for teeth in chickens slowly became obsolete and were “turned off” millions of years ago as reptiles made the transition into beaked birds and other avians. Researchers concluded that mutations with the talpid2 gene allowed the expression of these vestigial genes that no longer could serve a purpose in modern chickens.

Creationist Perspective
According to Creation Ministries International, this experiment reveals further information about the chicken biblical kind. When originally created, the chicken kind possessed a gene pool that would provide the possibility to grow teeth, in cases of environmental selective stress in favor of teeth. Applying this assessment, many fossils point to avian creatures with teeth, so the prospect that early chickens also retained that potential is not unreasonable. Creationists point to this case as an example of "devolution," where genetic information has been lost over time, not gained through Darwinism.

Similarly, fossils show platypuses with teeth, despite the fact that no platypus population today possesses teeth. The gene for teeth has been "switched off," yet no change in kind occurred. Essentially, the findings of Dr. Harris are consistent with a creationist's expectations when considering the high level of genetic variability at Creation. Many different kinds, including reptiles and birds, seem to have been originally provided with the same ability to grow teeth. However, use of these teeth in a selective environment has favored toothed reptiles but not necessarily toothed chickens. Additionally, observing a gene that has allegedly been "turned off" millions of years ago contradicts the fundamental beliefs of evolution. First, a loss of information would have taken place to remove teeth from avain gene expression. Second, according to evolution, genes that provide no function are eventually lost completely as natural selection allows unexpressed teeth genes to decay and mutate without adverse effects on the chicken. With this logic and span of time, chickens should possess zero ability to grow functional teeth in modern times; in any case, millions of years is not a workable influence.

Application
Through this study of dormant genetics, Fallon and Harris draw attention to its implications for evolution other than any direct medical benefit. Matthew Harris emphasizes, "There are so many examples of such atavistic traits -- snakes with vestigial limbs, horses with three toes, even human beings who have hair growing all over their body and face. As far as I am concerned, this experiment vindicates the theory of evolution as it exposes the evolutionary history of birds." Stephen Gould, a Harvard professor of evolutionary biology, proposes another perspective through this experiment. He explains that the fossil records shows few clean transitions between animals kinds; evolution likely occurs through major changes as a result of mutations in genes at the top of the gene hierarchy. In other words, most noticeable changes occur in genes that affect several other genes and therefore alter much of the physiology of the animal quickly.

The question must then be asked, "What, or Who, arranges genes in this hierarchical manner?" Stephen Jones, a Creationist biologist, offers, "what Harris demonstrated (albeit crudely) was not analogous to unintelligent `blind watchmaker' "evolution," but how intervention in normal natural processes by an intelligent agent can produce major changes in a single generation, which is analogous to intelligent design." Creationists find little issue with the presence of unexpressed genes that reveal a history of toothed avians. Studies like this simply draw more attention to an intelligent creator and His forbearance for various types of creatures. "The most ignorant dogma that continues to persist in our educational institutions is the notion that an Entity above mankind could not exist simply for lack of ability to measure by human means."

Video
See 12:24 for chickens' teeth discussion.

e39pyOxY7pg 0QVXdEOiCw8