What about those jumping genes?

I had an argument with crashfrog about jumping genes way back when (I can't find the thread.) It involved the discovery of tse-tse fly genes creeping around in the human genome. Well, this news from Nature is interesting and relevant to that issue. Here's a case of a fly getting its version of what happened to a human in the movie The Fly: Bacterial genome found within a fly's
DNA transfer from bacteria to animals is more common than thought.So maybe this supports the findings of insect genes in the human genome.The topical question for this proposed thead is: Do you think jumping genes could have played a significant role in the course of either biological or social evolution?”HM

CS responded to the question: A mutation can produce an allele of a gene”the simplest example being a single nucleotide polymorhism (SNP)”but OP article speaks to whole genes from prokaryotes jumping into the genome of an insect. That is much more dramatic than a SNP, wouldn't you say?”HM

My point is that genes jump further than you might expect, and indeed they can survive the leap intact, suggesting again, along with Dawkins, that genes have selfish determinism.”HM

crashfrog writes: What's the difference? Still seems like a real nifty HGT feat to me!”HM

crashfrog wrote: Just curious. Doesn't your sampling method differentiate between sampling contamination and HGT contamination? If not, you need to work on your lab procedures. Probably not. I've got young, beautiful women here distracting me while I'm trying to think. Then my investor calls and tells me to get out of the market right now. Birds are shitting on my boat. The next-door neighbor's pit bull is running loose again. Oh, and here come the grandkids to swim in my pool and mess up my kitchen...and you have the gall to ask me if I know what I am talking about?”HM Edited by Hoot Mon, : No reason given.

CS wrote: CS, if "selfish genetic determinism" doesn't get your attention, then I don't know what will. I'm taking Dawkins' and Hamilton's side in this consideration of jumping genes and their roles in evolution. I would like to know just how deterministically they jump. And, since genes are purely digital information, I wonder if that is somehow beneficial to their jumping. (Maybe the air is thinner up there in the digital world.)”HM

crash, the OP article is talking about a whole genome, you know.ADDED: Oops, sorry, I see that you have acknowledged this in your post.”HMEdited by Hoot Mon, : No reason given.

Good response. Write a letter to Nature and complain about this. They might print it. Otherwise, I don't know if anyone has ever brought up the possibility of "horizontal genome transfer" before. I find it quite remarkable, but what do I know with all these annoying distractions...(Jennefer, please, not now!)”HM

crashfrog wrote: Well, the OP article speaks to horizontal genome transfer, doesn't it?Re: HGT, an interesting a relevant exchange occurred recently in The Edge between Richard Dawkins (via John Brockman) and Freeman Dyson, concerning these two remarks made by Dyson:"By Darwinian evolution he [Woese] means evolution as Darwin understood it, based on the competition for survival of noninterbreeding species.""With rare exceptions, Darwinian evolution requires established species to become extinct so that new species can replace them."Dawkins comments:

quote:

---

These two quotations from Dyson constitute a classic schoolboy howler, a catastrophic misunderstanding of Darwinian evolution. Darwinian evolution, both as Darwin understood it, and as we understand it today in rather different language, is NOT based on the competition for survival of species. It is based on competition for survival WITHIN species. Darwin would have said competition between individuals within every species. I would say competition between genes within gene pools. The difference between those two ways of putting it is small compared with Dyson's howler (shared by most laymen: it is the howler that I wrote The Selfish Gene partly to dispel, and I thought I had pretty much succeeded, but Dyson obviously hasn't read it!) that natural selection is about the differential survival or extinction of species. Of course the extinction of species is extremely important in the history of life, and there may very well be non-random aspects of it (some species are more likely to go extinct than others) but, although this may in some superficial sense resemble Darwinian selection, it is NOT the selection process that has driven evolution. Moreover, arms races between species constitute an important part of the competitive climate that drives Darwinian evolution. But in, for example, the arms race between predators and prey, or parasites and hosts, the competition that drives evolution is all going on within species. Individual foxes don't compete with rabbits, they compete with other individual foxes within their own species to be the ones that catch the rabbits (I would prefer to rephrase it as competition between genes within the fox gene pool).

​

The rest of Dyson's piece is interesting, as you'd expect, and there really is an interesting sense in which there is an interlude between two periods of horizontal transfer (and we mustn't forget that bacteria still practise horizontal transfer and have done throughout the time when eucaryotes have been in the 'Interlude'). But the interlude in the middle is not the Darwinian Interlude, it is the Meiosis / Sex / Gene-Pool / Species Interlude. Darwinian selection between genes still goes on during eras of horizontal transfer, just as it does during the Interlude. What happened during the 3-billion-year Interlude is that genes were confined to gene pools and limited to competing with other genes within the same species. Previously (and still in bacteria) they were free to compete with other genes more widely (there was no such thing as a species outside the 'Interlude'). If a new period of horizontal transfer is indeed now dawning through technology, genes may become free to compete with other genes more widely yet again.

​

As I said, there are fascinating ideas in Freeman Dyson's piece. But it is a huge pity it is marred by such an elementary mistake at the heart of it.

---

Dyson replies:

quote:

---

Thank you for the E-mail that you sent to John Brockman, saying that I had made a "school-boy howler" when I said that Darwinian evolution was a competition between species rather than between individuals. You also said I obviously had not read The Selfish Gene. In fact I did read your book and disagreed with it for the following reasons.

​

Here are two replies to your E-mail. The first was a verbal response made immediately when Brockman read your E-mail aloud at a meeting of biologists at his farm. The second was written the following day after thinking more carefully about the question.

​

First response. What I wrote is not a howler and Dawkins is wrong. Species once established evolve very little, and the big steps in evolution mostly occur at speciation events when new species appear with new adaptations. The reason for this is that the rate of evolution of a population is roughly proportional to the inverse square root of the population size. So big steps are most likely when populations are small, giving rise to the "punctuated equilibrium'' that is seen in the fossil record. The competition is between the new species with a small population adapting fast to new conditions and the old species with a big population adapting slowly.

​

Second response. It is absurd to think that group selection is less important than individual selection. Consider for example Dodo A and Dodo B, competing for mates and progeny in the dodo population on Mauritius. Dodo A competes much better and”has greater fitness, as measured by individual selection. Dodo A mates more often and has many more grandchildren than Dodo B. A hundred years later, the species is extinct and the fitness of A and B are both reduced to zero. Selection operating at the species level trumps selection at the individual level. Selection at the species level wiped out both A and B because the species neglected to maintain the ability to fly, which was essential to survival when human predators appeared on the island. This situation is not peculiar to dodos. It arises throughout the course of evolution, whenever environmental changes cause species to become extinct.

​

In my opinion, both these responses are valid, but the second one goes more directly to the issue that divides us.

---

This exchange reminds me of other arguments waged here on EvC.”HM

molbiogirl responded to my statement: In 2000, New Scientist published an article titled Look before it leaps, reporting that tsetse-fly genes have "jumped," by way of mariner elements, into the human genome:

quote:

---

A "JUMPING GENE" being used to genetically engineer organisms has crossed the species barrier at least seven times in evolutionary history, in one instance between flies and humans, according to a study commissioned by the British government.

---

This always evokes a memory of the spiny hairs growing out of Jeff Goldblum's back in the movie The Fly. Well, maybe it's possible for a social-insect gene to turn a human being into a party animal. Paris Hilton come to mind.”HM
Edited by Hoot Mon, : No reason given.

crash wrote: I agree. Why does Creationism need a cause-effect mechanism to be validated? I always thought Creationism was above all that. Why would any logical explanation serve the needs of Creationism, or even ID? This harps back to the old question: Why does religion need to justify itself scientifically? I don't ever see science trying to justify itself religiously.”HM

crash wrote: But what about those mariner elements? Maybe transposons (on steroids?) are the mechanisms you're looking for. If they work for genes, then why not genomes? The OP article speaks to a whole genome jumping from prokaryotes to eukaryotes. That makes a jump from insects to humans look trivial by comparison. Do you think they should? I do.”HM

Naked DNA transfer is an interesting concept. Do you know of any mariner elements or transposons (if they are categorically different) that are able to operate apart from viral activity?”HM

molbiogirl asks: Only the one I posted to the abstract of the article. But I have a hard copy of the article somewhere in my files (I'm watching the Seahawks right now so I'm going to go dig for it). Thanks. I wasn't entirely sure. Thanks again. With you and crashfrog around I'll finally get things straight. No. Only fly genes. The only time I referenced whole-genome transfer was with respect to the OP artcile.”HM

molbiogirl,Thank you for that contribution. I think what you have written above pretty much dispells my fantasy about tsetse-fly genes hopping over into the human genome. It was fun while it lasted, but your argument is compelling....So much for genetic transmorgrification.”HM