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| Michael Marshall |
This morning, I got to wondering about the ratio of the mass of a being's genome to the mass of its body.
You know how Modernist Man is always oozing on and on about the great size of humans and dinosaurs and blue whales, compared to that of the bacteria, as proof of our greater complexity and hence, presumably, of our intelligence.
I was convinced I won't find any information on this ratio genome mass to body mass, because it won't flatter us humans at all.
I was right -- nobody seems to have asked the question.
If someone has - please feel free to correct me in spades.
(And by the by - somebody please sequence the genome of the giant blue whale and compare that mass to its body mass.)
The average bacteria weighs about 1 pico gram and its genome weighs about one thousand of a pico gram, for a ratio of about one thousand to one.
By way of contrast I should say the human genome, purely in terms of number (and hence mass) of basepairs, is about only 1000 times the size of the larger bacteria genomes.
In addition, the genes of a bacteria make up a far greater total of its genome than seems to be the case in that of humans, so we actually mightn't have many more genes than the bacteria does.
But the jury is still out - scientists find it hard to believe all the non-protein coding DNA inside of us humans is totally useless baggage.
Now when we weigh the human genome it weights about six pico grams and let us assume that the average human weighs about 60 kilograms (60,000 grams) (132 lbs), just for the ease of the math.
A one thousand to one ratio of genome to body mass should mean that a human genome should weigh 60 grams, not 6 pico grams.
In plain English, the human ratio ratio of genome mass to body mass is one to a trillion.
That is a ratio one billion times worse than that of the bacteria.
We humans, compared to bacteria, have big bodies but with comparatively small 'genome' brains.
Yes the organ we humans call a brain is very big, in ratio to our body weight, but the giant sulfur bacteria might considering it just another vacuole, only this time holding memories instead of sulfur.
To them, perhaps, the 'real' brain is the genome, because it allows a being to do more different things, rather than just doing a few things extraordinarily well as in the case of the human brain.
Good point - we have a K-selected genome - much more successful than the bacteria's in stable times.
Their genome, by contrast, is an r-selected genome - much more flexible than ours when times get tough and survival not success, is the key.
Think of it as the Margaret Atwood Law of Nature ( you might wanna look up her classic book called Survival to see what I mean ....)
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