Posted on 05/21/2003 4:53:28 PM PDT by blam
Genetic changes in mice 'question evolution speed'
A species of mouse has evolved dramatically in just 150 years, showing genetic change can occur much faster than was thought possible.
The discovery was made by accident by two American biologists studying the genetic make-up of a common wild mouse in Chicago.
Dr Dennis Nyberg and Dr Oliver Pergams, both from the University of Illinois at Chicago, analysed DNA samples from 56 museum specimens of the white-footed mouse dating back to 1855, and 52 wild mice captured from local forests and parks.
They found startling genetic differences between the 19th century and modern mice.
Only one of the present-day mice had DNA that matched that of mice collected before 1950.
While fast evolutionary change has been seen in fruit flies, such rapid evolution in a mammal has not been reported before.
The scientists, whose findings appear in the journal Nature, believe humans may have been partly responsible for the "new" mice.
"Settlers may have brought in mice with the favourable gene that were able to out-compete mice with the native variant," said Dr Pergams.
Story filed: 18:18 Wednesday 21st May 2003
From your comment here, I gather you have not read my linked reference by Shapiro.
You seem to have neglected to explain where, exactly, you think the contents of the Shapiro paper disagrees with what I wrote above. I do not see that it does.
Nor are you correct in your presumption that I haven't read his paper -- I have, which is how I was able to comment on its contents in my previous post. I have also read similar treatises through the years, which is how I was able to point out that Shapiro does not state anything that was not already under discussion in the literature.
That is not to say he is what you would term an ID'er
Quite the contrary, since he consistently mentions the "natural" processes at work.
• "Major evolutionary change to the genome occurs by the amplification and rearrangement of pre-existing modules. Old genomic systems are disassembled and new genomic systems are assembled by natural genetic engineering functions that operate via non-random molecular processes."
Yes, so? Such mechanisms would result from the "evolution of evolution" I was describing.
I don't have the relevant literature in front me at the moment, but for a taste from a quick web search:
Or can natural selection favour genes that produce evolvability? Can genes that cause genetic changes become established in a population because they improve evolvability, even though the population may experience long periods of environmental stability?One thing that a lot of people forget (including admittedly a lot of scientists) is that not only the externally obvious parts and the internal workings of an organism can change via evolution, but so can *the organisms genetic mechanisms itself*, because they, too, are part of the organism. People sometimes think of evolution as if it were computer code (DNA) changes made in the memory of an unchanging computer as it runs, but in this case the very "computer" itself -- the cellular machinery which copies, maintains, and "interprets" the DNA instructions -- is *itself* defined by genetic instructions. So not only the "program" can evolve, but so can the "computer" it runs on, in ways that can potentially improve the efficiency or workability of further changes. This is Shapiro's main point, and it's a good one. But it hardly implies ID, since evolution itself can evolve better evolution, so to speak.Theoretical work begun by American evolutionist Egbert Leigh in the early 1970's suggests that they can[19]. He was able to show that in restricted circumstances, natural selection will favour genes that cause populations to continually try out mutations. Further work carried out by a number of theorists has extended his conclusions to a wider range of circumstances and genetic changes[20]. This work has also shown that natural selection will favour genes that target their genetic changes so that the changes are more likely to meet future adaptive needs.
-- From this webpage. See the page for the footnotes
• "Major alterations in the content and distribution of repetitive DNA elements results in a reformatting of the genome to function in novel ways --without major alterations of protein coding sequences. These reformattings would be particularly important in adaptive radiations within taxonomic groups that use the same basic materials to make a wide variety of morphologically distinct species (e.g. birds and mammals)."
Again, this is just more of the same -- evolution has produced genetic mechanisms which are better at successfully evolving. In this case, they do so by having a tendency to shuffle entire sequences of genetic "building blocks" instead of leaving them in situ and relying only on single base-pair mutations.
• "Large-scale genome-wide reorganizations occur rapidly (potentially within a single generation) following activation of natural genetic engineering systems in response to a major evolutionary challenge. The cellular regulation of natural genetic engineering automatically imposes a punctuated tempo on the process of evolutionary change."
Ditto, see above. Organisms which had cellular "machinery" which was more conducive to successful adaptive evolution prospered more than those organisms which did not, by exactly the same process by which, for example, giraffes with longer necks fared better than their shorter-necked cousins when low-lying food became more scarce.
• "Targeting of natural genetic engineering processes by cellular control networks to particular regions of the genome enhances the probability of generating useful new multi-locus systems. (Exactly how far the computational capacity of cells can influence complex genome rearrangements needs to be investigated. This area also holds promise for powerful new biotechnologies.)"
More of the same (different mechanism, similar results) -- more successful evolutionary adaptation, which itself will be just as preferentially "chosen" by natural selection as the more "traditional" species traits (such as phenotype).
• "Natural selection following genome reorganization eliminates the misfits whose new genetic structures are non-functional. In this sense, natural selection plays an essentially negative role, as postulated by many early thinkers about evolution (e.g. 53). Once organisms with functional new genomes appear, however, natural selection may play a positive role in fine-tuning novel genetic systems by the kind of micro-evolutionary processes currently studied in the laboratory."
This is really a different point altogether, but again, one which hardly screams "ID" instead of more traditional evolutionary processes.
Please keep up with the class.
Nah, not my bag - I merely presented those posts to assist you with something that seemed to be an issue with you, but that you missed somehow. Perhaps your browser needs upgrading ;)
But since the subject is still two links from Talk-origins, I will further address their staleness apart from the "worm" claim contained therein which I demonstrated as unfounded long ago. In particular, the apple/hawthorn insect claim in the first link is not an example of speciation contrary to the claim in the title. The link does provide the reference from the scientists, who evidently presented the "evidence", which caution interpretations that would label the evidence speciation.
Ah, but just think how much more presentable that argument is than simply pointing to a date and acting as though that's the end of it. Despite the fact that we have occasionally gotten in each other's faces from time to time, I know you are quite capable of doing more than that, and your follow-up to my post serves to show that quite well, I think. As argumentative as you and I have been in the past on these threads, I think you are better than the sort of puerile idiocy as has been displayed by too many others here. And so I make a suggestion of a sort of pax evolva, and pledge to try to remain aboveboard in my posts to you in the future - in particular, by examining posts and evidence on their own merits, rather than by simply dismissing them for seemingly illogical reasons - and ask the same in return. And I ask it of you because I know that you and I are capable of it, despite our respective flaws - something which I doubt about a few others here lately....
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