If you start with everything then the only way you can go is backwards "devolution". Thus DNA shortens and potencial "products"and their traits become more specific. Its just a hypothesis i once had. The idea came when i read about amoebas and how large their DNA is. Thus very unspecified organism with enormous potencial.
The size of an organism's genome has no correlation to that organism's number of genes.
Genes that are not utilized are called 'junk'. Not meaning they are in the trash, but let's say "in the storeroom". Scientists do not allude that this is because the organism may have a future use, but if a future need arises, any of these genes are still available.
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In any case, a few caveats are in order regarding the high end of this range. First, these values for amoebae were based on rough biochemical measurements of total cellular DNA content (Friz 1968), which probably includes a significant fraction of mitochondrial DNA. The accuracy of this method is brought into question when one considers that Friz's (1968) value of 300pg for Amoeba proteus is an order of magnitude higher than those reported in subsequent studies (Byers 1986). Second, some amoebae (e.g., A. proteus) contain 500-1000 small chromosomes and are quite possibly highly polyploid (Byers 1986), in which case these values would be inappropriate for a comparison of haploid genome sizes among eukaryotes. Of course, this has little impact on the need to explain variation in genome size; it may just mean that these impressive examples will require replacement by some based on more reliable estimates."
http://www.genomesize.com/statistics.php
Polyploidy - a chromosome being duplicated, in cases over and over and over. (doesn't occur in humans but rarely, usually mistakenly).
Also, prevailing conditions, especially extremely variable ones, can greatly increase the need for precise 'turning on' of genes, for those that require such, and in this case, there is a higher chance of mutation also, unlike humans, whose mutations are usually on the spot:
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| In any case, a few caveats are in order regarding the high end of this range. First, these values for amoebae were based on rough biochemical measurements of total cellular DNA content (Friz 1968), which probably includes a significant fraction of mitochondrial DNA. The accuracy of this method is brought into question when one considers that Friz's (1968) value of 300pg for Amoeba proteus is an order of magnitude higher than those reported in subsequent studies (Byers 1986). Second, some amoebae (e.g., A. proteus) contain 500-1000 small chromosomes and are quite possibly highly polyploid (Byers 1986), in which case these values would be inappropriate for a comparison of haploid genome sizes among eukaryotes. Of course, this has little impact on the need to explain variation in genome size; it may just mean that these impressive examples will require replacement by some based on more reliable estimates." |
http://www.genomesize.com/statistics.php
Polyploidy - a chromosome being duplicated, in cases over and over and over. (doesn't occur in humans but rarely, usually mistakenly).
Also, prevailing conditions, especially extremely variable ones, can greatly increase the need for precise 'turning on' of genes, for those that require such, and in this case, there is a higher chance of mutation also, unlike humans, whose mutations are usually on the spot: However, under normal circumstances by far the greatest source of mutations is from endogenous mutation, notably spontaneous errors in DNA replication and repair.
http://www.ncbi.nlm.nih.gov/books/NBK7566/ Here's a short easy read:
Why Onions Have More DNA Than You Do http://www.news.harvard.edu/gazette/2000/02.10/onion.htmlThis publication is 11 years old, and obviously before the discovery presented by this thread.
Here's a link to ....well, I don't know if this is legit or not, but it is certainly interesting. it does have a 'crank' look to it though. If anyone can verify these people, please do so.
http://www.junkdna.com/So there is debate over exactly what junk DNA actually is, whether it should be called that, and whether it has a real though undefined purpose. The discovery of the treehopper's re-use of junk DNA will likely mitigate our view of this subject. The term may be abandoned, but scientists do point out that 'junk' doesn't exactly mean 'garbage in the trash can'.
As a final note on this post, IDers like to present the basic bias towards a smaller genome in bacteria as proof that de-evolution exists. What they don't admit is that the first bacteria were very simple, and that there are mechanisms in place that disallow key genes to degrade or be discarded. And most importantly, the mechanism to make new genes is always present. A genome slowly streamlining itself is not a de-evolution.
They DO make good table legs in your modern art coffee table.