Please Debunk my Creationist Boss

[BigMacnFries]

My Boss says that because genes are selfish, sexual reproduction would not evolve, as this would lead to a 50% reduction in the amount of genetic material that an individual passes on, in comparison to similar species/ subspecies, in which individuals pass on 100% of their genetic material.

I suspect this argument is fallicious but do not know enough about genetics/ evolution to understand why, please help.

 

[Orefa]

Genes are selfish? Are they also vane?

I say don't discuss the topic, switch to football and keep a happy workplace.

 

[Curious3141]

What the heck is your boss even talking about ? In sexual reproduction, each gamete contains 50 % of the genetic material of the parent. When the gametes fuse, a new organism is created that contains 100% of a full genetic complement, in turn comprised of equal parts maternal and paternal DNA. For each autosomal (non-X and non-Y chromosome) nuclear (non-mitochondrial) genetic locus of the offspring, one allele comes from the father and one allele from the mother.

In asexual reproduction, the full genetic code of one parent is 100 % copied out, with or without errors. End of story.

Your boss seems to be spouting off on the strength of cocksure ignorance.

 

[BigMacnFries]

Genes are selfish? Are they also vane.

If you haven't heard the term "selfish gene" before you really should't be answering posts on genetics. Richard Dwarkins uses it to metaphorically to state that the genes that favour their own replication the most, end up being the genes that exist in the future gene pool.

What the heck is your boss even talking about ? In sexual reproduction, each gamete contains 50 % of the genetic material of the parent. When the gametes fuse, a new organism is created that contains 100% of a full genetic complement, in turn comprised of equal parts maternal and paternal DNA. For each autosomal (non-X and non-Y chromosome) nuclear (non-mitochondrial) genetic locus of the offspring, one allele comes from the father and one allele from the mother.

I don't think you understand what it is I am asking. Yes this is basically the way that sexual reproduction works, neither I or my boss are disputing that. The point is that originally organisms reproduced asexually. From a genes point of view you have 100% chance of making it into the next generation. If you evolve into an subspecies that reproduces sexually, then this programme for sexual reproduction, wherever it exists on the genes, only has a 50% chance of making it into the next generation. Mathmatically speaking you would expect this kind of trait (sexual reproduction) to be bread out of the species before it could take off.

 

[Monique]

With sexual reproduction you create variety in a population, with asexual reproduction you drive a population to homozygosity. The sexually producing population will be better resistant to different stresses since it can adapt with every generation. Asexual reproduction does allow an organism to pass down twice the number of genes, but it will go to the cost of the above two mentioned short-term (genetic diversity) and long-term (adaptive evolution) advantages.

 

[iansmith]

There is a major disavatange with asexual reproduction, everybody in the population is the same. The lack of diversity may lead to the extinction of your genes because selective pressure may kill the entire population very rapidly.

So let assume you get two populations, one of clones and the other of non-clones. A viruse or bacteria comes in these populations. The viruses or bacteria is very efficient at killing and only a specific combination of genes will give you resistance to the virus/bacteria. In the clone population, almost 100% of the population dies as a results. In the other population, about 25% survive. So altought only "50%" of your genes were pass down, you still have progenity that is alive.

Basicly, the benefits of sexual reproduction is that it introduces a wide diversity which increases the probability that your progenity survives when certain type of selective pressure arise. However, this benefit is often seen for organism where generation rate is low and mutation rate is "low". In these organism, diversity via asexual reproduction would be introduce very slowly when compared to sexual reproduction. Asexual reproduction does benefit organisms that have a rapid generation time and a relatively high mutation rate. Diversity in this case can be introduced rapidly.

Evolution is all about benefits and if a benefit outweights the cost, then it will emerge.

 

[BigMacnFries]

Thanks, the last two replies made a lot of sense

 

[Orefa]

If you haven't heard the term "selfish gene" before you really should't be answering posts on genetics.

Oh, sorry for my weak attempt at humour BigMacnFries, I should have added a smily. I maintain my recommendation: I would not attempt to convert my creationist boss. It will most likely fail and merely cause frictions along the way. That's all I wanted to suggest.

 

[Mk]

I'm with Orefa on that one.

 

[Moonbear]

If you haven't heard the term "selfish gene" before you really should't be answering posts on genetics. Richard Dwarkins uses it to metaphorically to state that the genes that favour their own replication the most, end up being the genes that exist in the future gene pool.

This term actually refers more to population genetics than to actual individual genes. Individual organisms will do what they can to pass on their genes to future generations...i.e., reproduce and keep their offspring alive to reach reproductive maturity too. The strategies different species use differ. Some have tens, hundreds or thousands of offspring at a time, but don't bother to stick around to take care of them, so those that are fittest survive, and those that aren't, don't. With that many offspring, some off those offspring will carry each allele the parents have. Other species have just a few offspring, but spend a lot of time in parental care ensuring they reach adulthood (sexual maturity). Unless a gene is very rare in the first place, some proportion of the individuals carrying that gene will pass it on to the next generation, where it remains available when that next generation reproduces. This all requires large populations of course.

Genetic variation IS lost if the population isn't large enough to sustain it, and too much inbreeding occurs (look up founder effect or population bottleneck). Cheetahs are a good example of this, where every individual of the remaining population have nearly identical genes because so few remain that they're pretty much all inbred and have lost genetic diversity as a result.

 

[TRCSF]

I've not positive on this, but consider how sex evolved in the first place.

You've got little organisms that can reproduce asexually, but they can also shoot their dna into organisms. You've also got organisms that can accept foriegn DNA and use it to their own advantage. So basically you've got prototypical egg and sperm.

Then eventually through random mutation they lost the ability to reproduce asexually. So it was either reproduce with "50% of their genes" (that's not really true, it's still the whole genome, just one of two copies), or not reproduce at all. It's not a tough choice.

So now you've got a mutation that has a trait which has an advantage (that monique mentioned) and it's selected for.

Sounds to me like that's a great example of how evolution works, not the other way around.

 

[Phobos]

As TRCSF alludes to, a gene can still be passed on without being expressed in an individual. The "selfish" gene can thereby keep reproducing and, through recombination (sexual mixing of genes), "try on" different combinations of complimentary genes to see if a new combination* actually improves the reproductive success of that particular gene. (not meaning to personify of course)

* Physical traits in an organism are often the result of a combination of genes rather than a single gene.

 

[Rade]

My Boss says that because genes are selfish, sexual reproduction would not evolve, as this would lead to a 50% reduction in the amount of genetic material that an individual passes on, in comparison to similar species/ subspecies, in which individuals pass on 100% of their genetic material. I suspect this argument is fallicious but do not know enough about genetics/ evolution to understand why, please help.

But sexual reproduction did evolve--does not this fact falsify your boss's argument ? The fallacy of the argument derives from a false assumption that the environment of the Earth was stable during the time that only asexual organisms were present. Thus, what good to pass on 100 % of genes to offspring if environment changes such that only 1 % of offspring have adaptive advantage ? Much better to pass on 50 % if the genetic variety that results from union of gametes to form offspring has 2 % or greater adaptive advantage (you must understand process of meiosis here). Give your boss this test. Tell him/her to refuse to alter products sold in his business after customers demand new options--that is, to year after year sell only the same products (same as passing on same 100 % of genes generation after generation). I predict boss and business extinct within a short period of time.

 

[BigMacnFries]

But sexual reproduction did evolve--does not this fact falsify your boss's argument ?

This is such a bad example of begging the question it would make an excellent example for a philosophy textbook, or one on common sense. Otherwise I agree with your points on genetic diversity.

 

[honestrosewater]

This story reminded me of this thread.

... The new work could help test a hypothesis first proposed nearly 20 years ago, stating that sex evolved as a way to purge harmful mutations from a population. According to this view, the random shuffling of genes through sex will sometimes have the effect of concentrating many harmful mutations into single individuals.

These individuals will be less healthy than their peers, and therefore more likely to be weeded out by natural selection, the thinking goes.

This hypothesis, called the "mutational deterministic hypothesis," is controversial though, because it assumes that single mutations by themselves are only slightly harmful, while a combination of many mutations together is much more damaging. Scientists call this phenomenon "negative epistasis."

If negative epistasis were true, it would provide a powerful explanation for why sex has managed to persist for so long despite its numerous costs. But the phenomenon has yet to be widely demonstrated in nature and scientists have yet to figure out how such a thing evolved in the first place.

A new computer model by Ricardo Azevedo of the University of Houston and colleagues provides a possible answer to this last question. According to their model, detailed in the March 2 issue of the journal Nature, negative epistasis is a natural byproduct of sex itself.

-- http://livescience.com/animalworld/060301_evolution_sex.html

Paper (abstract): http://www.nature.com/nature/journal/v440/n7080/abs/nature04488.html
Same story: http://www.eurekalert.org/pub_releases/2006-03/uoh-swb030106.php

So MDH is supposed to explain the maintenance but not the origin of sexual repoduction, yes?

You might also be interested in Classification of Hypotheses on the
Advantage of Amphimixis (PDF), which runs through several, if not all, of the proposed advantages of sexual reproduction.

 

[Rade]

This is such a bad example of begging the question it would make an excellent example for a philosophy textbook, or one on common sense. Otherwise I agree with your points on genetic diversity.

You are correct, I did beg a question by assuming without evidence that your boss was in possession of common sense. But...as relates to sexual reproduction...my answer does not beg the question, because the "question" under discussion (that is, what was being debated) was whether or not "genes are selfish", not the well established fact that sexual reproduction in plants and animals evolved from asexual reproduction. No one on this thread conceded that sexual reproduction did not evolve--thus my answer cannot beg this question never conceded.
Here is a definition on the topic of question begging from internet:

The phrase "begging the question", or "petitio principii" in Latin, refers to the "question" in a formal debate—that is, the issue being debated. In such a debate, one side may ask the other side to concede certain points in order to speed up the proceedings. To "beg" the question is to ask that the very point at issue be conceded, which is of course illegitimate.

 

[Gokul43201]

Hmmm, and I thought all along that sexual reproduction evolved because it was more fun !

 

[Moonbear]

There are several publications by J.J. Crews where he hypothesizes that sexual behavior evolved before sexual reproduction in vertebrates. This is based on his observations of a parthenogenic species of lizard that despite the lack of need of sexual reproduction, the females still engage in reproductive behaviors very similar to the mating behaviors males and females (they can reproduce both sexually and asexually). It's been about a decade since I've read his work, so I don't know its current status, but I remember thinking it was really fascinating to have sexual behavior in a species capable of reproducing asexually.

 

[Schrodinger's Dog]

Oh, sorry for my weak attempt at humour BigMacnFries, I should have added a smily. I maintain my recommendation: I would not attempt to convert my creationist boss. It will most likely fail and merely cause frictions along the way. That's all I wanted to suggest.

I have some first hand experience of trying to reason with creationists both old creationists(believe the Earth is millions of years old) and young creationists(believe the Earth is 6000 years old) here's is my conclusion: if they can believe that they will believe anything after all they are fundementalists. Totally agree, you can argue for hours and no matter how much you destroy their case they will not believe you.

It's kind of fun to argue but in a work place, if your boss says I think DNA is actually God's lego(intelligent design) then just smile and back away quickly before the thing goes off