Evolving a Feather By Shuffling Parts

Science

#1

so by mixing parts in the genome we can get a feather for instance?


Constructive Neutral Evolution
(John Harshman) #2

Yes. Much of feather evolution involves the duplication and divergence of keratin genes.


#3

first: they are similar genes but not identical. so you cant just mix them and get a feather from non feather. second: how many of them we need to mix to get a feather?


(John Harshman) #4

Can’t really comment on either. The first makes no sense, and the second is rendered unanswerable by the word “need”.


#5

let me put it this way: how many changes we need to evolve the first feather out of scale?

as far as i aware we need about 5 genes to this conversion:


(John Harshman) #6

Bad way to say it. Did you read that paper? I suggest you also take a look at Prum & Brush 2002, referenced there. The first feather didn’t emerge from a scale. There’s a lengthy history between them, beginning with a single tubular filament. You’re using the “cat gives birth to a dog” model of evolution.


#7

but what make you think that its possible by small steps? the electric organ for instance is coded by about 30 genes. what make you think that such a system can evolve by small steps?


(John Harshman) #8

Because there are indeed small steps shown by developmental biology and paleontology? What makes you think is isn’t possible?


#9

What makes you think it is impossible?


Constructive Neutral Evolution
(George) #10

@scd,

Until you can be absolutely sure that each of those 5 genes doesn’t provide some benefit, no matter how unrelated to the benefit of “complete feathers” … you really cant know.


(Bill Cole) #11

So if for arguments sake I agree that we cannot prove the evolution of flight by natural means is impossible. What does that say for the theory of flight evolution. That it is simply possible. How likely is it? How many times do we have to accept it happened to agree that the evolutionary explanation is reasonable?


(George) #12

@colewd,

This is a matter of pure logic. This is why Joshua (and I) are absolutely convinced that there is no reason to think Science can ever reveal God’s affect on Evolution.

But men do not live by pure logic alone.

We already ACCEPT that God guides evolution, as a position of FAITH, and so we can already agree with @Scd that God made the feathers.

But this is exactly why I get so heated about people dwelling inordinately long on Godless-Evolution… newcomers think that’s what the important issue… old comers forget that we are not arguing about Guided Evolution…

and newbies of every stripe start to align themselves based on arguments about GODLESS evolution.]

How wrong do we have to be?

You, @colewd, you are an old hand at this… and even you get a little heated about my stance on something YOU ALREADY KNOW that I accept God’s leadership.

Relax. @Scd is not your fault.


(George) #13

@scd,

I prayed to God, and He gave me the best answer of all! You know those 5 genes you were worried about?

Well, in this article, one sample of a virus was blocked from infecting (and killing) a host. But in 8 days, everything would change!

To make a long story short, after just 8 days, one of six lambda populations evolved the ability to infect malT -mutated cells by attaching to a different surface protein, one called OmpF (short for outer membrane protein F). This evolved lambda virus could now infect E. coli cells through the original receptor, LamB, or this new one, OmpF. It had gained a new functional capability.

[5 NEW GENES IN 8 DAYS!]
To understand this change, Justin sequenced the genome of this virus. He found a total of 5 mutations compared to the lambda virus with which he had begun.

[5 Genes… HE SAYS 5 GENES 4 TIMES!]
All 5 mutations were in the same gene, one that encodes the J protein in the “tail” of the virus that interacts with the cell surface. He also sequenced the J gene for some other viruses isolated from the same population. He found one virus that had 4 of these 5 mutations, but which could not infect cells via the OmpF receptor. Did that mean that only one of the 5 mutations was necessary to evolve this new function?

As it turns out, the answer is no. To better understand what had happened, Justin scaled up his experiments and ran an additional 96 replicates with lambda, E. coli , and glucose. In 24 cases, the viruses evolved the new mode of infection within three weeks. Justin sequenced the J gene from the viruses able to target OmpF in those 24 cases, and in 24 other cases where the virus could still use only the LamB receptor. He found that all 24 with the new capability had at least 4 mutations; these included 2 changes that were identical in all 24 lines, a third that further mutated one of the same codons (sets of 3 DNA bases that specify a particular amino acid to be incorporated into a protein), and another mutation that was always within a span of 11 codons."

“All of these mutations cause amino-acid substitutions near the end of the J protein, which is known to interact with the LamB receptor. The J protein is over 1100 amino acids in length, and so this concentration and parallelism (repeatability across lineages) is striking and strongly implies that natural selection favored these mutations.”


#14

the fact that many complex biological systems cant function just by 1-2 genes. so if we have a system which contain about 30 genes, even if we assume that half of them are not necessary- we still need about 15 of them to make it work.


#15

i never said that we cant get a new function (we can get new function by chance even in men -made objects). actually to get a new binding site may be very easy (1 out of 10^11 random sequences are able to bind atp for instance). but these are simple functions and not complex system which contain many complex proteins.


(George) #16

@scd

Complex proteins have been demonstrated to have uses on their way to other functions.

What paper have you read that demonstrates that this cannot happen?


(John Harshman) #17

True. And if we assume that nine tenths of them are not necessary we need about 3 of them to make it work. Considering that we have fossil evidence of the gradual evolution of feathers, you are in the position of arguing that bumblebees can’t fly.


(Robert Byers) #18

If, aw shucks, one can evolve a feather then why not a diversity of featherish things?
Why is there any ceiling to what a feather can look like or be made of BUT still do the feather thing?
if mutations can do anything thenm why didn’t they?
The feather is a very closed system of a thing that needs to catch a wave of air.
by thw way I do think feathers appear where they were not before.
many birds must of developed feathers unrelated to previous body plans.
I remember watching the GREAT bird series by the brit , Attenborough?, truly great and famous,
he mentioned, if i got my facts right, a bird with a feather on its head that surely was a post fall/flood adaption. Yet it was aerodynamic. So it can appear out of nowhere. yet still the feather kind.


(S. Joshua Swamidass) #19

There is a diversity of feathery things! :slight_smile:


(Retired Professor & Minister.) #20

Yes, feathers do a really great job of catching a wave of air, AKA serving as excellent insulation. They keep feathered animals (i.e., birds) very warm indeed, even in some of the coldest weather.