Gavin Da Beer stated homology is a problem for the theory of evolution? Is there an answer?

Question

He sums up why homology is a problem for the theory of evolution as follows:

What mechanism can it be that results in the production of homologous organs, the same 'patterns', in spite of their not being controlled by the same genes? I asked this question in 1938, and it has not been answered.

Although some 30 years have passed since de Beer wrote those words, they have still received no answer?

The discovery which really overthrew homology is that organs accepted as "homologous" are almost all controlled by very different genetic codes.

Is there a scientific response to this, that would gave support to theory of evolution?

This statement can be find on ID, and creationist sites when they try to refute homology as evidence for evolution. I was confused with this statement and since genetics isn't my field of study didn't know what to make of it.

References: Gavin De Beer, Homology: An Unsolved Problem, London: Oxford University Press. 1971, s.16

Answer 1

I am not aware of any evidence that shows that homologous structures are controlled by different genetic codes. Do you have a reference for that?

UPDATE: I have found some of the references which the ID/Creationist crowd take wildly out of context (as usual) in the mistaken belief that it supports their ideology.

The last reference De Beer made to this homology 'problem' was in 1971 - long before DNA sequencing and genetic manipulation had developed to the point that they have more or less explained this 'problem'.

In the case of genetic control of homologous structures - most of them have been found to be under the control of multiple gene sequences at different parts of their development. There is no simple - one gene/one structure set-up.

In many cases, the genetic control over the development of homologous structures is also under the influence of environmental factors, such as where signalling proteins are present in different stages of the development process. By manipulating these variables, scientists are able to do things like produce eyes on the wings of flies, or legs in place of eyes. Simple mutation or variation can account for how homologous structures can originate in different embryonic layers.

Answer 2

I cannot improve on the other two excellent answers except to stress that this is a common technique used in creationist sites to engage in blatant deception.

They take a scientist with a good reputation, ignore his entire life's work except for a couple of short sentences, and then use that quote over and over as evidence of scientists "conceding" problems.

In short, cherry-picking. Choosing *just* the little snippets of of a scientist's work that *hints* at a flaw in evolution, and ignoring the bulk of the scientist's body of work that supports evolution, and led the scientist to remain a staunch 'evolutionist'.

There are three forms of this.

First, as in this case, a scientist may actually be pointing out a problem that his research is detecting that he has no answer for. That doesn't mean there is no answer, only that (a) his research may be wrong; or (b) his research may be right and producing a new question that needs to be answered. This de Beer case is a good example ... Gavin de Beer was writing specifically about genetic homology, not homology in general, and wrote this in 1971, before we understood much about DNA sequencing and how there is not a one-structure-one-gene relationship.

So creationist sites *love* to quote a scientist pointing out a problem, but conveniently omit the fact that other scientists have since solved the problem.

The second class of deception is quoting a scientist partially ... often called "quote-mining." The most common example is quoting Darwin from Chapter 6 of Origin of Species, where Darwin considers objections to his theory and then refutes them. Creationist sites *love* to quote Darwin expressing the "problems", but then omit Darwin's immediate refutation of the problem.

And the third class, which is the lowest of the low, is to simply invent something that the scientist did not say. The classic example is the so-called "deathbed recantation" of Darwin (also known as the Lady Hope story, after the evangelist woman who claimed to have converted Darwin at his deathbed).

In all cases the purpose is the same ... when unable to refute scientists directly, or to produce a scientist of equal reputation, they use the good reputation of that scientist to contradict everything they believed.

This kind of deception is easy to spot. Whenever you see a web site or book quoting a respected scientist saying what seems to be the exact *opposite* of their entire life's work ... then there's a good chance that there is more to the story. If a scientist supposedly found a fatal flaw in evolution, then ask yourself why they would still firmly remain in the 'evolutionist' camp. Maybe it's because they understood what they were saying better than the people who misquoting them.

Please remember that!

Answer 3

I'm not aware of any responses (or even of this theory until now), but how can homologous structures NOT support evolution?

The presence of similar structures in different species just shows that different lines of organisms developed similar methods of solving a problem given their choice of genes to manipulate. So, butterflies, differentiated from other insects and having those genes, used membranous structures in order to fly; birds, descending from reptiles, used the strong bones and muscles that had been characteristic of their genetic lineage. So how is that a problem for evolution? Seems like excellent support to me.

The mechanism here is a combination of mutation and natural selection. Those butterflies and birds that could fly better were more fit for the environment in that they could obtain food and escape predators more efficiently and quickly. The gradual change in genetic makeup was due to mutations that allowed for such structures and behaviors to develop, since mutation is the ultimate source of variation. Again, this just supports evolution.

Maybe there weren't a lot of scientific responses because the idea was too preposterous.

Answer 4

Fantastically well put. Give haysoos, lamictalfan, and secret all 10 points. I'm just horning in for 2 of my own.

Here's a source that expands on haysoos's and lamictalfan's explanation...sorry, it's not electronic (that I know of):

Carroll, Sean B. 2005. Endless Forms Most Beautiful. New York: W. W. Norton.

Answer 5

These are still problems—homologous structures that are not produced by homologous genes or the same embryological development, or homologous structures in animals that are not suppose to have a close common ancestor (no evolutionary relationship), and so forth.

But the thing is, homology can just as easily point to a common designer; it fits quite comfortably with the creation model.

As Dr. Don Batten has said, “Think about the original Porsche and a Volkswagen ‘Beetle’ cars. They both had air-cooled, flat, horizontally-opposed, 4-cylinder engines in the rear, independent rear suspension, two doors, trunk in the front, and many other similarities. Why did these two very different cars have so many similarities? Because they had the same designer!”

And as Dr. Jerry Bergman said, “...the requirements of life are similar for similar living things, and some designs are preferred in constructing animals because these designs are superior to competing designs. All automobile, bicycle and pushcart tires are round because this design is superior for the function of most tires. A tire homology does not prove common descent, but common design by engineers throughout history because of the superiority of the round structure for rolling.”

Dr. Carl Weiland said the same: “By its very nature, creation involves the intelligent application of design information, which it would seem logical to conserve. For example, if the pattern of the forelimb bones in a frog works well, following good bioengineering principles, then it would seem reasonable for the same principles to be used in the other creatures, modified to fit their particular needs.”

Oh, and here are some more questions for you from Dr. R.L. Wysong:

1. The octopus eye, pig heart, Pekingese dog’s face, milk of the ***, and the pronator quadratus muscle
of the Japanese salamander are all very similar to analogous human structures. Do these similarities
show evolutionary relationships?

2. The weight of the brain in proportion to body weight is greater in the dwarf monkey of South America,
the marmoset, than in man. Since this proportion is used to show relationship between primates
and man, is the marmoset, therefore, more evolved than man?

3. The plague bacterium (Pasteurella pestis [now known as Yersinia pestis—BT]) afflicts only man
and rodent. Does this similarity show close relationship?

4. Plant nettle stings contain acetylcholine, 5-hydroxytryptamine and histamine. These chemicals are
also found in man. Are man and plant closely related?

5. The root nodules of certain leguminous plants and the crustacean, Daphnia, contain hemoglobin, the
blood pigment found in man. Are these organisms closely related to man?

6. If certain specific gravity tests are run on the blood of various animals, the frog and snake are found
to be more similar to man than the monkey is to man.

7. If the concentration of red blood cells in animals is compared (millions per cubic millimeter of
blood), man is more similar to frogs, fish, and birds than he is to sheep.

8. Since bones are often used to show relationships, bone chemistry should be useful in this regard. If
the calcium/phosphorus ratio is plotted against bone carbonate, man proves to be close to the turtle
and elephant, the monkey close to the goose, and the dog close to the horse but distant from the cat.

9. The tetrapyrole chemical ring is found in plant chlorophyll, in hemoglobin and other animal respiratory
pigments, sporadically as a coloring pigment in molluscan shells, and also in the feathers of
some bird species. How does tetrapyrole similarity speak for relationships?