The Funny Side of Religion

liamw

recedite wrote: »

Why does he say sex is a mystery; surely its evolutionary purpose is to mix and match more gene combinations?

I'm pretty sure he's referring to the initial origins of sex. How male and female species evolved together, rather than the current benefits of sexual over asexual reproduction.

seamus

Evolution, innit? Clearly sexual reproduction is/was the best way of producing the best offspring in many environments.

Mark Hamill

Goduznt Xzst wrote: »

Well if genes want to propagate themselves, it's curious that we evolved the need to mix our genes in with a competing set of genes and invariably reduce the amount of unique genes that we can propagate by half.

But wouldn't those unique surviving genes be the stronger genes? It might only be stronger only in terms of genetic natural selection, but maybe a genes dominance over other genes during reproduction reflects on its ability to consistently develop beneficial biological systems in humans?
(I'm no expert in this, this was just a thought that occured to me and could be completely wrong).

Goduznt Xzst wrote: »

We could of evolved the ability to just procreate without the need for sex and passed on 100% of our genes.

Where is the fun in that?

Goduznt Xzst

seamus wrote: »

Evolution, innit? Clearly sexual reproduction is/was the best way of producing the best offspring in many environments.

Yes, but you lose half your genes in the process. The mystery is "why" this was the best option that was selected for. The current leading hypothesis is that bacteria, parasites et al put so much consistent pressure on our genes to adapt that the lesser of two evils was to dump half of our genes with each generation to create enough variation to try and stay ahead of the parasites.

It's still a mystery though whether this was actually the case. Dawkins himself follows the gene-centered view of evolution so obviously genetic sharing for procreation is a bit of an aberration to this theory. On the face of it, a "selfish" gene, should not select for reducing the amount of genes by half, with each successive generation, that get passed on. So there was clearly some environmental pressure put on the organism that selected for gene mixing.

What that pressure was is the mystery.

Mark Hamill wrote: »

But wouldn't those unique surviving genes be the stronger genes? It might only be stronger only in terms of genetic natural selection...

This would be true, if you followed an organism-centered view of evoltion. Gene mixing benefits the organism, but damages the genes.

liamw

Goduznt Xzst wrote: »

Gene mixing benefits the organism, but damages the genes.

It doesn't damage the gene (reduce it's popularity in the gene pool), if the chance of survival and reproduction outweighs the loss of probability in being passed on.

i.e. In an asexual environment the gene has near 100% chance of being copied but the individual may only have less than half the offspring as it would have had in a sexual environment (due to the many survival/adaptability advantages of sexual reproduction).

mikhail

recedite

Also, lets say 2 cooperating parents, eg birds, are feeding 4 chicks in a nest. Each chick carries 50% genes. If the 2 adults had been able to reproduce separately, asexually, each adult could only feed 2 chicks of 100% genes. Therefore; same rate of selfish gene propagation, but with less recombinations. More recombinations gives better immunity and adaptability, therefore better prospects for the selfish gene.
I suppose this only applies to the higher cooperative animals though.

Goduznt Xzst

liamw wrote: »

It doesn't damage the gene (reduce it's popularity in the gene pool), if the chance of survival and reproduction outweighs the loss of probability in being passed on.

i.e. In an asexual environment the gene has near 100% chance of being copied but the individual may only have less than half the offspring as it would have had in a sexual environment (due to the many survival/adaptability advantages of sexual reproduction).

You keep flip-flopping from a gene-centric view of evolution to an organism-centric view of evolution. It is advantageous for the organism to mix genes, but it is detrimental to the genes themselves to do so.

It does damage the gene to mix with a competing foreign gene to survive. After a few successive generations the original genes will have all but been replaced by the new organisms plethora of mixed genes. The mystery is what pressures forced the genes to select for this. A pressure that forced the genes down a path that would ultimately destroy it's uniqueness.

Anyway, rather than go on about it anymore in this thread, I've found a link with Dawkins explaining the sex conundrum briefly.

http://bigthink.com/ideas/17050

robindch

Goduznt Xzst wrote: »

You keep flip-flopping from a gene-centric view of evolution to an organism-centric view of evolution. It is advantageous for the organism to mix genes, but it is detrimental to the genes themselves to do so. [...] After a few successive generations the original genes will have all but been replaced by the new organisms plethora of mixed genes. The mystery is what pressures forced the genes to select for this.

Dawkins believes that the influence of genotypic selection outweighs the influence of other classes of selection. Hence, in that video, he says (but doesn't emphasize) that he's talking about the genes'-eye view, backed up fairly rigorously by research and theory developed by Hamilton and others. In this system, the origin of sex is something of a mystery since it does appear to be deleterious to genes, at the gene level.

Other classes of selection, such as cell-level, phenotypic, group-level and species-level and multi-level have allowed other explanations to be developed, but to date, there's no fully-convincing answer that I can think of and the question is still open.

liamw

Goduznt Xzst wrote: »

You keep flip-flopping from a gene-centric view of evolution to an organism-centric view of evolution. It is advantageous for the organism to mix genes, but it is detrimental to the genes themselves to do so.

Suppose we have GeneA1 in a sexual system and GeneA2 in an asexual one.

The host in which GeneA1 lives has 4 children. GeneA1 will average in 2 of those offspring.
The host in which GeneA2 lives has 1 child. GeneA2 will average in 1 of those offspring.

I have a feeling I'm wrong here though, so I'll just back out and watch the video :pac:

recedite

I see now the confusion arises; because the original concept of a gene was "an inheritable trait". In this model, sexual reproduction confers an advantage if more than two offspring survive, per pair of parents, compared to each individual cloning itself.

In a more correct modern technical definition, a gene is a small piece on a strand of DNA. This obviously gets destroyed when the DNA unwinds during reproduction. However the trait carries on. Perhaps The Selfish Allele would have been a better name for the book, and Dawkins would be less confused now.
The term genotype generally refers to the whole organism, so it's not useful for describing the individual trait.

robindch

recedite wrote: »

The term genotype generally refers to the whole organism, so it's not useful for describing the individual trait.

Nope, that's phenotype you're thinking of. The genotype is the genetic makeup, usually with reference to a single specific feature.

recedite

Ah no. Identical twins with different fingerprints exhibit the same genotype, but different phenotype.

Improbable

recedite wrote: »

Ah no. Identical twins with different fingerprints exhibit the same genotype, but different phenotype.

Monozygotic twins have the exact same genetic make up (if we exclude mutations which occur post-fertilization). Fingerprints are different because they are affected by environmental factors as well. It's only extreme cases where twins display different phenotypes.

Goduznt Xzst

sensibleken

recedite wrote: »

Ah no. Identical twins with different fingerprints exhibit the same genotype, but different phenotype.

Ive seen twins exhibit much worse on the internet

strobe

IBG


In before Galvaseoioaeouaieenn..... .....Gaviscon.

In before Gaviscon.

amacachi

strobe wrote: »

IBG


In before Galvaseoioaeouaieenn..... .....Gaviscon.

In before Gaviscon.

Thief.

Dermot2468

Saw a van for these guys the other day.

http://www.fsm.ie/

Have to say I lol'd

Galvasean

strobe wrote: »

IBG


In before Galvaseoioaeouaieenn..... .....Gaviscon.

In before Gaviscon.

I literally have this URL on my clipboard and came here especially to post it.

Now, who isthis Gaviscon lad?

keppler

Improbable

Dermot2468 wrote: »

Saw a van for these guys the other day.

http://www.fsm.ie/

Have to say I lol'd

This is probably going to be something really simple, but I don't get it...

keppler

Galvasean

Improbable wrote: »

This is probably going to be something really simple, but I don't get it...

F.S.M.

Improbable

Galvasean wrote: »

F.S.M.

Oooooooh, yes, I see. Never seen the abbreviated form before. Very amusing indeed.

Pushtrak

Turtwig

keppler wrote: »

Such is His grace that He saw fit to do it by having an moon sized object (with potential for life) torn to shreds by His perfectly designed gravitational force and have its remains left floating around the planet for years to come so that His people on earth may see the ring as a thing of aesthetic beauty. Makes perfect sense.

liamw

Dermot2468 wrote: »

http://www.fsm.ie/

Have to say I lol'd

Blasphemers! Burn them at the stake!

recedite

Dermot2468 wrote: »

Saw a van for these guys the other day.

http://www.fsm.ie/

Have to say I lol'd

Go on then, enlighten us. Is it something to do with the logo? Was something similar used by Devilworshippers (scraping the murky depths of my memory now)

Galvasean

recedite wrote: »

Go on then, enlighten us. Is it something to do with the logo? Was something similar used by Devilworshippers (scraping the murky depths of my memory now)

Galvasean wrote: »

F.S.M.

*ahem*