Scientists may have mapped how the ancient flying-dinosaurs- called Archaeopteryx- evolved into our modern world birds. Paleontologist Dr Bhart-Anjan S. Bhullar and biologist Dr Arhat Abzhanov from Yale University, have created a Chicken with a dinosaur face after suppressing the genes responsible for the development of its beak.
What was the reason for this experiment?
The original endeavor of the team was to understand the transformation of the beak which has been an integral part of the more than 10,000 species of birds. The aim was to unearth what was the skeletal and functional underlying aspect of beaks and when this transformation of beaks from a regular vertebrate snout took place. Creating a “dino-chicken” was not a part of the plan, however, this anatomical change has definitely interested a lot of researchers now.
Skull of a Velociraptor- whose palate configuration is found to be similar in birds
Initial observation made by the Scientists
Following were the observations that the team of scientists made in the case of reptiles and birds:
1. The team of scientists analyzed the embryonic development of beaks in chickens and emus, and of snouts in alligators, lizards and turtles. They found that reptile and dinosaur snouts develop from premaxilla in a similar way but the development was altered in the case of birds.
2. The team found that two proteins known for the development of the face, FGF and Wnt, were expressed differently in bird and reptile embryos. This led to Dr. Bhullar assuming that altered FGF and Wnt activity resulted in their beaks.
How was the genetic modification achieved?
Birds have a unique cluster of genes which are related to their facial development which are not present in non-beak creatures. The team studied the changes in the gene expression inside the embryo of chickens and other animals. DNA was extracted from alligators in order to clone fragments of genetic material to look for specific gene expression. The unique cluster of genes was then suppressed and the result of this procedure was that the beak reverted to its ancestral state, into a snout, and the palatal bone on the roof of the mouth also rolled back into its ancestral shape.
CT scans showing a regular chicken embryo skull (left), altered chicken embryo skull (middle) and the alligator embryo skull (right)
In order to make the genetic tweaks, the scientists isolated the proteins that promoted the development of beaks by using tiny beads coated with an inhibiting substance. By stopping the bird-specific patch of molecular activity from taking place in the middle of the embryo’s face, the skeletons of these animals had short, rounded bones instead of elongated, fused beaks that bird skeletons have.
An artist’s rendition of Archaeopteryx
Dr. Bhullar also stressed over the fact that this procedure did not change the DNA of the animals but simply altered the gene expression. The embryo’s were then humanly euthanised and the scientists were not allowed to grow the embryo’s into full chicks.
What this experiment means?
It has been widely understood that after the asteroid which wiped out almost all of the dinosaurs from Earth, a species of dinosaurs that were the aviation types or Archaeopteryx survived and later evolved into birds. This species had wings and feathers like a bird and was thus, widely believed to be the ancestors. This experiment goes on to impose the affirmation on this fact.
By tweaking just a little part of the bird genome, it is safe to say that scientists have discovered the transcendence of how the tip of the dinosaur snout grew to become the major part of the bird beak, while the toothiest part of the dinosaur jaw shrunk to almost nothing. The specimens whose gene expressions were inhibited developed a snout and palate configuration similar to that of small dinosaurs such as the Velociraptor and Archaeopteryx. The results of this experiment are published in the journal Evolution.
[sources: 1, 2, 3]