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Glenn Morton wrote (in part):

*>Date: Wed, 20 Sep 2000 14:06:26 -0500 (CDT)
*

*>From: mortongr@flash.net
*

*>Subject: Random chance brings meaning
*

*>...
*

*>We are going to test these ideas, that random sequences can't create
*

*>information. And if genes are like words and sentences as Kenyon and Davis
*

*>claim, then I will show that random sequences CAN create information.
*

Glenn presented the Vignere code, an encryption-decryption method, to

demonstrate that random processes "CAN create information". He shows

that a

21-letter message encoded by a random 21-letter key can be "decoded" by

9

other random 21-letter keys to yield 9 different meaningful messages.

In fact, it is quite easy to obtain such solutions: select a meaningful

21-

letter phrase, take its first (second,...) letter, locate it in the

first

row of the Vignere code table, go down this column to the first

(second,...) letter of the coded message and look up the first letter in

this row: this is the first (second,...) letter of the new "random" key.

Repeat this for the 21 letters.

For instance, take the message 'RandomOriginOfEnzymes': the procedure

yields the key 'yeslsxvafodpqduiwwqtt'. Apply this "random" key to

decipher

Glenn's original coded message 'pefogjjrnulceiyvvucxl' and you'll obtain

'RandomOriginOfEnzymes'!

But of course, that's cheated, because we worked backwards!

There are 26^21, or about 5.2 x 10^29 (that's 520,000 trillion

trillion),

different 21-letter strings of 26 possible letters. How many meaningful

phrases of 21 letters might there be? 1000? a million? a trillion? I

don't

know. I haven't written a computer program to try to get an estimate.

The

"natural selection" routine required for this program must be quite

involved, including a parser, a dictionary, some expert system

algorithms,

as well as a user-friendly interface for a human to evaluate the

tentative

solutions proposed by the program. But maybe Glenn, who certainly did

not

cheat, can provide us with such an estimate. What's your hitting

average,

Glenn?

Manfred Eigen, Nobelist and inventor of the hypercycles, also cheated by

working backwards. In popular lectures about the origin of life, he used

to

present a computer simulation purporting to show that information can

indeed emerge quite rapidly by means of random "evolutionary" processes.

He

generated a random sequence of letters, which he mutated randomly. Each

time a letter happened to equal the corresponding letter of a meaningful

phrase previously deposited, it was and remained fixed. Of course, the

process produced the "information" supplied after not too many

generations!

But let's look more closely at what really happens in evolution! Hubert

P.

Yockey ("A calculation of the probability of spontaneous biogenesis by

information theory", J.theoret.Biol. 67 (1977), 377) compared the then

known sequences of the small enzyme cytochrome c from different

organisms.

He found that 27 of the 101 amino acid positions were completely

invariant,

2 different amino acids occurred at 14 positions, 3 at 21, etc., more

than

10 nowhere. Optimistically assuming that the 101 positions are mutually

independent and that chemically similar amino acids can replace each

other

at the variable positions without harming the enzymatic activity, he

calculated that 4 x 10^61 different sequences of 101 amino acids might

have

cytochrome c activity. But this implies that the probability of

spontaneous

emergence of any one of them is only 2 x 10^(-65), which is way too low

to

be considered reasonable (it is unlikely that these numbers would change

appreciably by including all sequences known today). A similar situation

applies to other enzymes, such as ribonucleases.

Thus, a modern enzyme activity is extremely unlikely to be found by a

random-walk mutational process. But "primitive" enzymes, near the origin

of

life, may be expected to have much less activity and to be much less

sensitive to variation. Unfortunately, before someone synthesizes a set

of

"primitive" cytochromes c, we have no way of knowing the effects of

these

factors.

What we can do, however, is to estimate how many invariant sites can be

expected to be correctly occupied by means of a random walk before a new

enzyme activity becomes selectable by darwinian evolution (of course,

such

an invariant set may be distributed among more sites which are

correspondingly more variable, without affecting the conclusions). So,

let's start with some extremely optimistic assumptions (cf. P. Rüst,

"How

has life and it's diversity been produced?" PSCF 44 (1992), 80):

Let's assume that all of the Earth's biomass consists of the most

efficient

biosynthesis "machines" known, bacteria, and all of them continually

churn

out test sequences for a new enzyme function, which doesn't exist yet in

any organism. They start with random sequences or sequences having a

different function. Natural selection starts only after a minimal

enzymatic

activity of the type wanted is discernable. In today's biosphere, t =

10^16

moles of carbon are turned over yearly, there are n = 10^14 bacteria per

mole of carbon, a bacterium is taken to have b = 4.7 x 10^6 base pairs

in

its DNA. This yields R = tnb = 4.7 x 10^36 nucleotide replications per

year

on Earth.

In protein biosynthesis, there are c = 61/20 = 3.05 codons per amino

acid,

a = 2.16 mutations per amino acid replacement (geometric average of all

possible shortest mutational walks in the modern code table), a mutation

rate of 1 mutation in m = 10^8 nucleotides replicated. Therefore, r =

1/(c(3/m)^a) = 5.8 x 10^15 nucleotide replications are required for 1

specific amino acid replacement (the factor 3 represents the codon

length

in the triplet code).

In order to get s specific amino acid replacements, r^s nucleotide

replacements are needed, and the average waiting period for 1 hit

anywhere

on Earth is W = (r^s)/R. For s = 1, W = 4 x 10^(-14) seconds; for s = 2,

W

= 4 minutes; for s = 3, W = 40 billion years!

Thus the minimal set for a starting enzymatic activity cannot contain

more

than 2 specific amino acid occupations! Of course, for the origin of

life,

biosynthesis "machines" like bacteria were not yet available, and

certainly

not in an amount equalling today's biomass! Does it still sound

reasonable

to assume that biological information is easily generated by random

processes? Or is there something wrong with the model underlying the

above

estimate?

If God used only random processes and natural selection when He created

life 3.8 billion years ago, we should be able to successfully simulate

it

in a computer. You may even cheat: the genome sequences of various non-

parasitic bacteria and archaea are available. The challenge stands. By

grace alone we proceed, to quote Wayne.

Peter Rüst

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