There's a story out about "dino-chickens":
To understand how one changed into another, a team has been tampering with the molecular processes that make up a beak in chickens.
To begin to understand this, the team trawled though changes in the ways genes are expressed in the embryos of chickens and several other animals. They looked at the embryos of mice, emus, alligators, lizards and turtles, representing many of the major animal groups.
They found that birds have a unique cluster of genes related to facial development, which the non-beaked creatures lacked.
When they silenced these genes, the beak structure reverted back to its ancestral state. So too did the palatal bone in the roof of the mouth.
To make this genetic tweak, Bhullar and his colleagues isolated the proteins that would have gone on to develop beaks. Then they suppressed them using tiny beads coated with an inhibiting substance.
http://www.bbc.com/earth/story/20150512-bird-grows-face-of-dinosaur
The team found that two proteins known to orchestrate the development of the face, FGF and Wnt, were expressed differently in bird and reptile embryos. In reptiles, the proteins were active in two small areas in the part of the embryo that turns into the face. In birds, by contrast, both proteins were expressed in a large band across the same region in the embryo. Bhullar sees the result as tentative evidence that altered FGF and Wnt activity contributed to the evolution of the beak.
To test this idea, the team added biochemicals to block the activity of both proteins in dozens of developing chicken eggs.
http://www.nature.com/news/dino-chickens-reveal-how-the-beak-was-born-1.17507
It's a fascinating experiment. No doubt some impressionable readers will consider this to be the best evidence ever for evolution. By silencing certain genes, you can watch evolution in reverse. Rewind the evolutionary tape to view an earlier stage. We see it happen right before our very eyes!
Reminds me of a TNG episode ("Genesis") in which crew members deevolved. Even if you believe in evolution, the episode was ridiculous. Admittedly, Riker was typecast to play a caveman. But you have Barclay becoming a spider, Troy becoming a giant salamander, and Worf becoming a venomous snapping turtle.
Seems to me the inference that suppressing certain genes caused the chicken to deevolve is fallacious.
i) Anyone who knows anything about birds knows that many birds have specialized beaks which are adapted to their particular diet, viz. flamingo, pelican, hawk, huron, hummingbird, duck, woodpecker, sandpiper, toucan, crossbill, spoonbill. The configuration of the beak is less about time (the past) than space (the environment). They have, or develop, the beak they need to capitalize on a particular food source or food stuff.
A number of waterfowl have serrated beaks to grasp slippery food items. The appearance is quite similar to the genetically modified chicken.
ii) Creationism doesn't deny common ancestry. Creationism denies universal common descent. But creationism grants that many current species derive from earlier species. Moreover, current species reflect adaptive modifications to their environment.
For instance, some bats are insectivorous, some bats are frugivorous, and some bats are hematophagous. Now, it's possible that if you blocked certain proteins, the embryo would revert to a common ancestral form. But these are microevolutionary variations.
Likewise, I assume it's possible to reverse selective breeding so that dogs might revert to a more lupine appearance. But I suppose that depends on whether artificial breeding caused a loss of genetic information.
Seems like an excessive amount of time, money, and effort just to harelip a bunch of chickens.
ReplyDeleteIn addition to Steve's fine points:
ReplyDelete1. I haven't read the paper, but it looks like they only did what they did to chicken embryos. They didn't let the chicks hatch. But how can one draw the conclusion that the chicken de-evolved into its alleged dinosaur ancestor from halting the gene-silencing process midway? There's so much that could still happen to the chicken embryo before it hatches.
2. Say I'm building a commercial airplane. Like an A380. Say halfway through the construction process I decide not to put the wings or tail on the plane, so the plane looks sort of like a bus or or train or subway train. Say the plane was never completed. Say someone later happened upon this half-completed plane. Could this person therefore validly conclude that this wingless and tail-less plane must've been an old predecessor to the modern plane?
Also, check out this piece from Casey Luskin.
DeleteAm I the only one who catches the bitter irony that evolutionists have put forth an intelligently designed organism as proof that intelligent design is false?
ReplyDeleteGene expression is tricky business. One can grant that most organisms or lifeforms on Earth share a common genetic code. That's not a huge issue, I don't think.
ReplyDeleteIn addition, we can alter the genetic code in many different ways which we're still learning all about today. (Although obviously there are ethical issues here.)
But just because, for example, we can program or re-program or de-program a particular organism's genetic code to produce proteins which seem characteristic of a second organism (e.g. by gene silencing, by gene knockout, by introducing DNA from the second organism into the first) doesn't necessarily mean the two organisms let alone species share a common ancestor. They may, or they may not, but we'd need to take a closer look at other factors.