March 11, 2006 at 1:45 pm #11404
I am posting this piece as a good example of how far removed i believe that western science is from the energetic and spiritual reality underlying sexuality. Darwinists really have to stretch their imaginations to come up with complex explanations of why splitting the human sexes is an improvement over parthenogenesis (androgynous self-reproduction) used by majority of species on earth.
I prefer a simpler explanation – splitting the sexes was an accident, with uniintended consequces, that continued to multiply over time.
WHY WE HAVE SEX: IT’S CLEANSING
ACT EVOLVED AS A WAY TO PURGE HARMFUL MUTATIONS, NEW MODEL SHOWS
By Ker Than
March 2, 2006
Scientists have long wondered why organisms bother with sexual reproduction.
It makes a whole lot more sense to just have a bunch of females that can
clone themselves, which is how asexual reproduction works.
Turns out sex might have evolved as a way to concentrate lots of harmful
mutations into individual organisms so they could be easily weeded out by
natural selection, a new computer model suggests.
The classic explanation for the onset of whoopee, about 1 billion years ago,
is that it provides a way for organisms to swap and shuffle genes and to
create offspring with new gene combinations that might survive if the
environment suddenly changes.
But some scientists think this isn’t enough of a justification to outweigh
the many costs of getting together to make little ones. Just ask any single
person — sexual organisms have to spend valuable time and resources finding
and attracting mates.
If all organisms were like starfishes and cacti, which just drop pieces of
themselves when they want to multiply, reproduction would be a whole lot
simpler. There would be no need for elaborate peacock feathers or bird
songs; stags wouldn’t need antlers; elephant bulls wouldn’t have to produce
stinky cologne and guys probably wouldn’t spend so much money on dates.
The new work could help test a hypothesis first proposed nearly 20 years
ago, stating that sex evolved as a way to purge harmful mutations from a
population. According to this view, the random shuffling of genes through
sex will sometimes have the effect of concentrating many harmful mutations
into single individuals.
These individuals will be less healthy than their peers, and therefore more
likely to be weeded out by natural selection, the thinking goes.
This hypothesis, called the “mutational deterministic hypothesis,” is
controversial though, because it assumes that single mutations by themselves
are only slightly harmful, while a combination of many mutations together is
much more damaging. Scientists call this phenomenon “negative epistasis.”
If negative epistasis were true, it would provide a powerful explanation for
why sex has managed to persist for so long despite its numerous costs. But
the phenomenon has yet to be widely demonstrated in nature and scientists
have yet to figure out how such a thing evolved in the first place.
A new computer model by Ricardo Azevedo of the University of Houston and
colleagues provides a possible answer to this last question. According to
their model, detailed in the March 2 issue of the journal Nature, negative
epistasis is a natural byproduct of sex itself.
The researchers created digital organisms that reproduced through sex in the
same manner as real organisms. And like a regular organism, the virtual one
developed a natural buffer to resist change by mutations. This ability,
called “genetic robustness,” is thought to be one of the main benefits of
By shuffling genes, sex allows a population to spread its mutations across
many individuals within a group. The mutations become diluted and can be
effectively dealt with by an individual’s genetic repair system.
But the researchers found that the protection only works when the digital
organisms were facing a few mutations at a time. When assaulted by many at
once, their repair systems became overwhelmed and the organisms died.
Azevedo think this happens in real life, too.
“Most organisms are never forced to adapt to being resistant to many
mutations at once,” he told LiveScience. “They’re adapting to being
resistant to one or maybe two mutations, but not to ten at the same time.”
The researchers think that the combination of genetic robustness through sex
and the limited ability of organisms to deal with mutations leads to the
natural development of negative epistasis.
“Most mutations are actually harmful, so anything that helps populations get
rid of their harmful mutations is going to be important,” Azevedo said. “The
more interesting side of evolution is all the beneficial mutations that
leads to complex structures, but the dirty work of evolution is to get rid
of bad mutations, and that’s where sex seems to play a role.”March 31, 2006 at 5:49 am #11405
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