@glipsnort @knor @rsewell @mitchellmckain @RichardG @adamjedgar @GJDS @heymike3 @klw @paleomalacologist
Sorry to interrupt the discussion. I am tagging you because mynpost will soon disappear in the stream of bot spam in the forum. Mods know about it. The mess is bigger than they can handle with their tools. They will be reaching out to the BL office as soon as possible.
Kendel
I’ve posted in a few other public and private threads. Feel free to pass the word to anybody I missed,
I get that even with reproduction and mate selection, but I’m wondering what exactly is random with genetic variation.
If mate selection is random with respect to fitness, there has to be someway to distinguish that kind of randomness with respect to the ‘noise’ that is found when the gene is copied.
A more recent estimate puts the numbers around the same.
If an organism can target modifications to its own germline DNA so that they are adaptive, then no, those changes would not be random with respect to fitness. They would represent non-Darwinian evolution.
However, organisms can’t modify their germline DNA in a way similar to how the immune system works, because the immune system modifies its DNA by repeated rounds of random mutation and selection under exposure to the environmental threat. There’s no analogue for that for germline mutations (other than Darwinian evolution itself). Some other mechanism would be needed.
Mate selection is generally non-random with respect to fitness. Even in rather non-selective situations, some individuals will tend to have more offspring than others. But the process is not idealized; the markers used to identify a preferable mate are not perfect, there is some random variation, and there are ways to cheat the system (but which are subject to selective pressures). For example, the red patch for a male red-winged blackbird is the key indicator used by females to assess appeal. Although maintaining the color well requires good health, unsurprisingly one factor doesn’t capture everything. Experimentally, manipulating it can be very misleading. Paint over the red patch, and the male can do a fine display and never get a second look. Add extra red, and all the females are after him - even blatantly unnatural red. The red is a shoulder/wing patch. But you can’t use a red leg band to mark a male red-winged blackbird for a biological study, because that small amount of red in the wrong place still draws all the females.
The immune system modification is just a special case of natural selection on random mutations because it’s in extra high gear. It’s cranking out lots of mutations in the particular gene regions. Most of those are useless, but if one happens to find an intruder (or mistake something legitimate for an intruder), then that one is rapidly selected for to build the defenses. The immune system is trying to stay at least one jump ahead of the pathogens, and does so by lots of jumping in random directions; if one of those happens to be the right direction then it works. Likewise, at more normal mutation rates for the general genome, any given mutation might be useful, harmful, or irrelevant under a given set of conditions. If it is useful, the mutation will tend to persist and get inherited; if it is harmful, it will tend not to (though there is mathematical randomness there, too).
The “many more bacterial than human cells in us” claim was a guestimate that went viral as a “fact”.
I thnk it needs a complete shutdown for at least 24 hours.
Richard
Yes, it would be random with respect to fitness. V(D)J recombination gives rise to antibody and cell receptor genes. This happens during embryonic development in the absence of exposure to antigens. These mutations are random with respect to fitness. When a B-cell binds an antigen and is stimulated to reproduce and kick out more antibody this also induces somatic hypermutation that changes the gene that codes for the antibody, as well as many other hotspots in the genome nor related to immunity. These mutations are also random with respect to fitness because they are just as likely to reduce the binding specificity of the antibody to its antigen as it is to improve it.
Not if those edits are random with respect to fitness. Again, we conclude mutations are random with respect to fitness because that is what we observe in experiments. No matter what causes those mutations, they are observed to be random. These processes are just as likely to produce a beneficial mutation as they are a neutral or deleterious mutation. There is no statistical correlation between the mutation an organism needs in a given environment and the mutations it gets, regardless of how those mutations are produced.
Mutations are random with respect to fitness, not genetic variation within a population. Mutations that confer an advantage are passed on at a higher rate and are therefore found at a higher percentage within the population than we would expect by chance. Mutations that are harmful do the opposite. There’s a reason why mutations that confer lactose tolerance are increasing in the human population while mutations responsible for cystic fibrosis continue to be found in far fewer individuals.
Mike, it seems like the “wall you can’t cross” is that something could be considered ‘random’ (even just with respect to anything at all) and yet still represent a kind of “progress” (much less an ‘intended progress’ in any sort of Divine scheme of things). It sounds to me like your mind has two hard buckets, and the one labeled ‘random’ is where all meaningless and nonteleological things must go; and the ‘intentional’ or ‘divine’ or ‘human will’ bucket is where all progressive actions go. The notion that natural selection might work with randomness in order to ‘craft’ anything towards the biological realities we see now just blows a brain fuse for you, right? Like ‘craft’ and ‘random’ just cannot go together? Even when an impersonal mechanism (natural selection) is used to explain that the results on populations over time are not random?
I don’t think so. I’ve seen God work in the midst of some extremely chaotic events. He just doesn’t always work that way. So that’s not really an issue. I very much agree with the sentiment of other evolutionary theists on the forum.
What interested me was Noble seemed to be tugging on a curious thread of the Neo-Darwinian garment. And as I looked further into the subject I had and still have some doubt about what exactly is random with respect to fitness (I still have to read a couple recent comments, so it’s possible it was explained already).
It’s a bit like drawing a card from the deck in most card games. You purposefully draw a new card, but this purposeful act doesn’t guarantee that the drawn card will help your hand. The draw is random with respect to the fitness of your hand.
“Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.” -Colossians 4:6
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