Random news genes?

[Pierre Equey]

I read a very interesting web page yesterday: http://www.nwcreation.net/geneticrecombination.html

But, something seems to be very strange in the state of our knowledge in genetics. Here, scientists commonly say: "News species appear through accumulation of mutation over millions of years".

-o-O-o-

But... if we recombine randomly DNA nucleotides, we usually get pathogenic genes, not good (eugenic) ones. Furthermore, a lot of these pathogenic genes are simply lethal…

(DNA is a very long molecule, which in fact is a kind of database, containing the building-plan of its host living being) in the heart of our cells. DNA is made up sequences of four things called "nucleotides": A for Adenine, C for Cytosine, G for Guanine, T for Thymine.)

-o-O-o-

For example, if we imagine a very small eugenic gene of 4 nucleotides TATAGAGA and if the next closest eugenic gene is GAGATATA. Then, the distance between these two colleagues-genes seems to be 126'988 permutations. Quite huge, no?

T1 - TATAGAGA -> Eugenic, creates life-friendly proteins
T2- GATAGAGA -> Pathogenic , builds (maybe lethal) life-hostile proteins
T3- GGTAGAGA -> Pathogenic , builds (maybe lethal) life-hostile proteins
…
T126986 - GAGATAGG -> Pathogenic , generates (maybe lethal) life-hostile proteins
T126987 - GAGATATG-> Pathogenic , generates (maybe lethal) life-hostile proteins
T126988 - GAGATATA-> Eugenic, creates life-friendly proteins

-o-O-o-

With real-life genes (containing maybe more than 1000 nucleotides) things worsen. The distance between 2 eugenic genes is bigger as barn: 10^4'260'988 permutations.

-o-O-o-

I have to calculate more precisely the permutations; but nevertheless, they seem to be very huge... It is maybe very hard for a pinguine-family to have an elephant offspring.

[Bruno Groucha]

Hello my friend

Here are a few modest thoughts I submit to your venerable self :

An individual is defined by what differentiates it from its peers while a species is defined by what unites a number of individuals.
To mingle these two aspects is I think misleading if not fraudulent.

Genetic recombination produces a lot of very different individuals or breeds (as in creating new dog breeds) but from an evolution-of-species point of view, without an added "ingredient" it will only create more of the same (all dogs can cross-breed, none of these breeds constitutes a new species).

Here, scientists commonly say: "News species appear through accumulation of mutation over millions of years".

Actually this affirmation is widely debated among paleontologists.

Of course most DNA mutations are not beneficial, but given that they occur all the time, only a tiny fraction of them needs to be harmless or, better, helpful to become one of the driving forces in evolution.

Steven Jay Gould for example thought that evolution is not a continuous linear process through eras but a limited number of "leaps" triggered by a small number of DNA mutations, without noticeable changes in between.
To become the start of a new species, according to him, a mutation needs to occur in an isolated population where endogamy will ensure that the new genes won't dilute through reproduction (which would foretell a stop of human evolution in a globalised world...).
Later the new species will be subjected to natural selection when confronted to others.


For example it seems that the first ancestors of birds that developed wings were using them as inner temperature regulators, but their ratio body-weight/wings-length was too high to allow them flying.
Then some new species with a smaller ratio weight/length-of-wings appeared and was able to take-off, probably not a full flight at first, but that's when genetic recombination might have stepped in and turned them into today full-blown birds.

Anyway the main driving force of evolution seems to be not God, as the article you read implies, but chance, the fact that some mutations or combinations will be experimented and others not occur at all.
So if we went back to the beginning of life and started all over again, a completely different world would emerge.

[Platinium]

http://wapedia.mobi/fr/G%C3%A9nome_humain :

"On estime le nombre de gènes chez l'Homme à environ 30.000. Ces estimations ont été rendues possibles depuis le séquençage du génome humain. Cependant, les estimations varient encore, donnant des chiffres compris entre 20.000-25.000 et 40.000.

Notons par ailleurs que la majorité du génome humain est composée de séquences ne codant pas pour des gènes. Ces séquences correspondent notamment à des régions régulatrices de l'ADN.

Ainsi, la taille du génome humain est approximativement de 3,2 milliards de paires de nucléotides. Ainsi chaque cellule humaine contient 2 mètres d'ADN environ."

Thus, would you please calculate the number of permutations in human DNA ?
After that, tell me which is the probability to get a human DNA if the nucleotides ( 3.2 billions ) are associated randomly...

[Pierre Equey]

In facts, in real life, misspelled words will cause our ads to go extinct. A misspelled ad with garbage characters can't compete with a correctly spelled one - nobody will respond to it. Misspellings are not what we want and they are not good!

So the chances of evolving Brown to Black in one step are one chance in 65 to the power of 5, which is one chance in 1,160,290,625 (just over one in a billion). Random mutation does not create negentropy, it only destroys negentropy...