UK scientists believe they have discovered why the spread of "good
genes" throughout the population does not make everyone good-looking.
If women select the most attractive men, the genes should quickly become
commonplace, according to Darwin.
But the new research suggests that genetic mutations routinely affect
the DNA repair kit, resulting in greater variations as damage goes
unrepaired.
The findings, by Newcastle University, are published in the journal
Heredity.
Critics of evolutionary theory claim that widespread physical
differences among sexually selecting species such as humans are proof
that Darwinism is flawed - the so-called "lek paradox".
However, the new research by Professor Marion Petrie and Dr Gilbert
Roberts suggests that sexual selection can in fact cause greater genetic
diversity by a mechanism not previously understood.
 'Disease defending'
The scientists claim that since genetic mutations can occur anywhere in
the genome, some will affect the DNA repair kit possessed by all cells.
As a result, some individuals have less efficient repair kits, resulting
in greater variation in their DNA as damage goes unrepaired.
Professor Petrie said: "We started this research 10 years ago and our
model has now produced a good fit with what we observe in terms of
genetic variation, which leads us to believe that our theory is correct.
"We find that sexual selection can promote genetic diversity despite
expectations to the contrary."
It has long been known that greater variation of DNA in the disease
defending regions makes it more likely that an individual can resist
attacks by bacteria and viruses.
(Sourced from BBC News online) |
