Question For Evo's Re: Fruit Fly Mutations

It would be evolution as long as the hairyness was genetic and the next generation of dogs was also hairy as a result, if the hairyness was solely due to phenotypic variation then it wouldn't be.

Zealot writes:

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Woudln't this be natural selection, instead of evolution ?

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Natural selection is part of evolution.How can you select what isn't varied to begin with? Unless you're going to say that there is no such thing as mutation....------------------
Rrhain
WWJD? JWRTFM!

One possible example of a beneficial mutation that even YEC would have to agree with would be human skin color. Evo's mostly agree with an out of Africa theory for human population growth and YEC's believe in a migration from the Ark. If we are to assume that in both cases skin color was homogenous, then we have to account for the current heterogeneous range in skin color.Melanin is the chemical responsible for dark skin and provides DNA protection from UV damage. However, melanin also lowers the bodies ability to synthesize vitamin D. So, when sunlight is plentiful vitamin D is easy to make but UV damage can be a problem, ergo darker skin nearer the equator. When sunlight is not abundant (away from the equator), UV damage is less of a problem than vitamin D synthesis. Therefore changes in skin color is an adaptation to the amount of sunlight available. I can't point to the exact mutation/s responsible for this, but it would be a strong possibility. Children from parents of different skin color are often intermediate to the parents, which would suggest a non-dominant homozygous genotype. That is, skin color is decided by equal expression of the "melanin" genes given by both parents.Like I said before, I am not sure on the genetics behind skin color, and would be open to any information. However, even YEC's have to admit that skin color variation is an example of evolution (change), quite possibly an advantageous mutation.

Isn't it a matter of "adding up" genes for melanin production? I.e. the more copies you have between your two copies of the chromosome it's on, the darker your skin?isn't that why if a light-skinned person and a dark-skinned person have a child, the child has a skin tone somewhere in between?

Well, I agree with natural selection, but I dont particularly really see that a Creationist disagreeing with natural selection for instance. Its pretty clear that a stronger organism will survive if its gene's are more suited to the environment, and same with its children, however I dont see mutation as neccesary for this to occur.Again I use the example of putting an african man, a japanese man and a red headed man in the desert. The african man will survive and procreate and doesn't need any mutations to do so.I dont know if I'm correct, but I believe Creationists are of the opinion that we all possess abilities to produce various different looking offspring, thus that would account for the differences. I have no idea, but by your argument I'm curious as to where the genetic diversity originated from in the first place ? Is it just a case of single cell amoeba mutating ?thanks for your input.

Right, because he already has the mutations. Remember you're born with all the mutations you'll ever have - in terms of the ones you can pass on to your progeny.The question is, where did the traits that separate your three men come from? The answer is mutation. But that's not right. What you posess is the ability to pass one of two copies of each of your genes onto your children. So if your children are born with a gene that you don't have, and your mate doesn't have, then where did that new gene come from? Mutation. This does happen. Like I mentioned in another thread you have some 4 to 50 genes that neither of your parents have. Largely they don't do anything, or else you'd have noticed. Here's a hint - it starts with an M. That's right, mutation.

Only 4-50? Thats less than I would have expected. Anyway, I was just wondering if you could give me the source of your info. Thanks!

That's a lot, actually. Consider how many people are born every generation.And of course, that's assuming you're completely average. I wouldn't be surprised to find out that you had as few as 2 (or even none at all), or as many as 500, or 5000. It would really depend on what mutagenic factors your parents exposed their gametes to. It's mostly an estimation based on the fact that your average mammal genome experiences some 3 or 4 substitutions per billion base pairs per year. This figure is from Page and Holmes's Molecular Evolution: A Phylogenetic Approach, a standard graduate text on the subject.This message has been edited by crashfrog, 10-08-2004 05:01 PM

Beneficial mutations? I can think of many. Double pairs of wings, wingless, red-eyes, these have proved highly beneficial to fruit flies! Why? Because for every bizarre defect in them, we breed them by the billions for our own use. By having no wings, fruit flies are guaranteed to have large populations all over the globe from science labs to hobbyists who breed them to feed baby reptiles! A large number of scientists consider domestication an evolutionary strategy. Fungus that are grown by leaf cutter ants, sheep raised by ranchers, they're healthier and happier than their wild counterparts and remain well-fed and procreating even when the environment is not conducive, because they're being fed and protected!

gazaahA quick tip. There are two ways to reply. If you click on the large reply button at the bottom it posts a general reply to the thread. But there is also a smaller reply under each message with a red arrow. If you use that button it will connect your post to the message you're replying to. It makes it easier to follow the threads.

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How pierceful grows the hazy yon! How myrtle petaled thou! For spring hath sprung the cyclotron How high browse thou, brown cow? -- Churchy LaFemme, 1950

Interesting question - the vast majority of fruit fly experiments are genetic in nature but are not focused on creating or observing mutations. That said, radiation induced mutation studies using drosophila melanogaster (aka fruit fly, vinegar fly) were a bit of a fad a couple decades back. Unless an experiment is specifically designed to watch for it, if they had a beneficial mutation, we likely wouldn't even notice.However, with careful observation we might. I would need to look up the reference, but I believe there was a case among these radiation-based mutation experiments where they managed to generate a new line of fruit flies which lived more than twice as long, required less sustenance, and were measurably "stronger" as well. (How they measured the last, I can only imagine.)My favourite, however, was the mutated fruit fly who was born, walked in an arc which became an ever decreasing circle, and, having spiraled to a point in the centre simply turned around once and died.I suspect this was a fruit fly "performance artist" trying to demonstrate how an efficiency expert might view and express the futility of life. (That could be viewed as a beneficial mutation by the bleak-minded.)Cheers!

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Hugh
Dead Easy Fruit Fly Traps Homepage - Get a Trap Here!

Good point there; beneficiality is not a good measure, as sometimes a loss of a function can be beneficial; for example, a wingless fruit fly might survive better on an island with strong winds than those with wings. But they lost the function of flight. That doesn't explain how the wing evolved in the first place.

Okay, I put "drosophila AND increased fitness" into the pubmed search engine, and the first article that pops out gives an account of radiation-induced mutations in laboratory populations of drosophila including:1. decreased adult body weight
2. increased locomotor activity
3. increased metabolic rate
4. slightly reduced female fecundity
5. increased resistance to starvation
6. increased resistance to heat shock
7. increased lifespanAll of these apart from 4. can be considered beneficial under certain environmental conditions. 5,6 and maybe 7 are presumably what the creationists wanted to know about.The reference is Biogerontology. 2004;5(5):327-37.A minimal amount of research will often disprove the assertions of creationists (who have usually done even less research that oneself!)Regards,Mick

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Right, because he already has the mutations. Remember you're born with all the mutations you'll ever have - in terms of the ones you can pass on to your progeny.

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Strictly speaking, this is not true, at least if you are a man. Most mutations are errors during the replication of DNA, and in male germ line cells most replication (i.e. most cell divisions) occur after sexual maturity. Men keep producing sperm as they age, and the sperm have more and more mutations. This is presumably why males have much higher mutation rates than females.

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Like I mentioned in another thread you have some 4 to 50 genes that neither of your parents have.

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Estimates of the human mutation rate give a somewhat more precise estimate, around 50 to 100 new mutations per birth. (And of course these aren't actually new genes, but changes anywhere in the genome, most of which does not consist of genes.)

I was referring to mutations expressed in the phenotype, but you're technically correct, of course.