For a real world example, see:
This is creationist abductive reasoning – IF it were true that mutations chip away at the genome on average it would be a problem for evolution… so lets just endlessly repeat the made up claim that they do.
When in reality land mutations add, remove, and modify traits. That’s why everyone isn’t getting shorter and shorter every generation, your kids might be shorter or taller or have bigger feet or smaller feet, or more hair or less hair. If the world worked like creationists claimed it would be a one-way cycle to oblivion (which would’ve happened a long time ago btw).
You’re right!!! It would have went to oblivion a long time ago…. if the world is billions of years old, but not if it’s only a few thousand years old 🙂
P.S. – genetic entropy has been confirmed in a couple papers recently: http://www.uncommondescent.com/intelligent-design/recent-papers-confirm-that-genetic-entropy-decreases-fitness/
No, if it were thousands of years old and even 1% of mutations were harmful we would be extinct. Mutations are extremely common, more than 100 on average per person per generation. As for the link, all it is doing is quoting real scientific findings out of context. Google “quote-mining”.
Genomes are very redundant with lots of fallback systems. Humans all have hundreds of pseudogenes already. According to physiologist Dennis Noble in this talk (https://www.youtube.com/watch?v=QMVfafAYTMg?t=19m40s) at 19:40:
1. “Is this an unusual result, … or is it general? This study went through all 6000 genes in the organism yeast. knocking them out one by one. 80% of the knockouts were silent. So this physiological process of buffering against gene change is general. It’s usual in fact. Now that doesn’t mean to say that these proteins that are made as a consequence of gene templates for them don’t have a function. Of course they do. If you stress the organism you can reveal the function. .. If the organism can’t make product X by mechanism A, it makes it by mechanism B.”
“If even 1% were harmful”
I’d say at least 10-20% are harmful: (http://justpaste.it/2dlm) 10% is under functional constraint–meaning if common descent is true, anything that mutated that sequence since a common ancestor didn’t live to tell about it. ENCODE put 20% as strictly functional based on the amount that participated in binding sites and other very specific mechanisms.
How do you arrive at a figure of us being extinct after 1000 years?
Yes genomes contain redundancies but not for everything, and there is a difference between populations of bacteria being able to adapt by falling back on older mechanisms and being deleterious-mutation-proof as you seem to imply.
As for your links some genes being “restricted” does not, as you are trying to imply, mean that they can’t mutate or that mutations always do harm, it just means that mutations make a difference. And studies have shown over and over that most of those differences are benign. But you don’t need to look at studies, you should already know what I am saying is true just from personal experience. There is hardly a part of the human body that is not commonly different from one person to the other and most of those differences do not result in crippling deformities. Having kinky hair or curly hair or wavy hair doesn’t translate into being bald. Most mutations are benign and while it’s hard to estimate the percentage of mutations that change structure it’s easy to figure out exactly how many mutations happen per person per generation which as I said is over 100 per person on average, and often upwards of a thousand if someone has children at an advanced age. That translates into a higher (but still small) chance of having a birth defect, not your child having a hundred birth defects, which would be true if your estimate was accurate. And if 10% of mutations were harmful that would mean the human race would’ve been accumulating on average over ten birth defects per person per generation for hundreds of generations. How could we not go extinct?
And btw I said thousands of years, not one thousand years, though I think we’d probably go extinct almost immediately.
Every genetics paper I’ve ever read where a deleterious rate is calculated (probably nearly a dozen) did so by multiplying the total rate by the strictly functional rate. They estimated the functional amount either by counting regions where we know must have a specific sequence to function (e.g. protein coding exons + binding sites as ENCODE did in my link above), or by measuring conserved sequences between species.
Now the part where your mistaken is that you think every deleterious mutation is going to cause a birth defect. Even ignoring all of the buffering from redundant genes, most deleterious mutations will just reduce the stability of a protein fold, weaken a binding site, upregulate or downregulate transcription, or some other effect that could make proteins slightly less effective at doing their job. A little more cholesterol accumulates in your arteries, or you have a higher risk of breast cancer. Every now and then you’ll get a frameshift or an inversion that creates a stop codon and wipes out a gene completely, but that’s less frequent. Even then, many genes themselves will only have a minor effect when knocked out. Deleterious mutations follow a bell curve, with minor ones being the most frequent and major ones being rare. But like rust, the minor ones can still accumulate until your bumper falls off or you get epilepsy.
So why don’t we all have epilepsy?
Thank you for this post! It is such a shame that so many are so brainwashed that they don’t even realize how they automatically make the wrong assumptions and look at everything backwards. They don’t even realize how much assumption goes into their own ideas they mistake as fact.
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Grace with Salt
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