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Why some people are more attractive than others
March 28, 2007Paradox of evolutionary theory, often cited by creationists, is explained at last
Researchers believe they have solved a mystery that has puzzled evolutionary scientists for years ... if 'good' genes spread through the population, why are individuals so different?
The so-called 'lek paradox', that sexually-selecting species like humans should have much less individuality than is the case, has been seized upon by creationists as an argument that Darwin's theories are fundamentally flawed.
The problem with current evolutionary theory is that if females select the most attractive mates, the genes responsible for attractive features should spread quickly through a population, resulting in males becoming equally attractive, to the point where sexual selection could no longer take place.
However, new research by Professor Marion Petrie and Dr Gilbert Roberts at Newcastle University, England, suggests that sexual selection can in fact cause greater genetic diversity by a mechanism not previously understood.
Professor Petrie theorised 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 does unrepaired.
Although unrepaired DNA is generally harmful-causing tissue to degenerate or develop cancers-it is useful in some parts of the genome, such as those parts resposible for disease defence where variation can help in the resistance to disease. 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.
Using a computer model to map the spread of genes in a population, Professor Petrie demonstrated that the tendency towards reduction in genetic diversity caused by sexual selection is outweighed by the maintenance in greater genetic diversity generated by mutations affecting DNA repair.
The research is published today (28 March 2007) in the academic journal, Heredity, part of the Nature Publishing Group.
Professor Petrie, of the Evolution and Behaviour Research Group in the School of Biology at Newcastle University, said: 'We started this research ten 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.'
In 2005, Professor Petrie and colleagues demonstrated that men with greater genetic diversity in disease defence regions of the genome — and therefore better prospects of passing disease resistance to their offspring — had a number of physical features which women found attractive. The research involved testing men for genetic diversity and showing photographs of them to women, who allocated scores for attractiveness. These scores were found to correlate strongly to genetic diversity.
University of Newcastle upon Tyne
The problem with current evolutionary theory is that if females select the most attractive mates, the genes responsible for attractive features should spread quickly through a population, resulting in males becoming equally attractive, to the point where sexual selection could no longer take place.
However, new research by Professor Marion Petrie and Dr Gilbert Roberts at Newcastle University, England, suggests that sexual selection can in fact cause greater genetic diversity by a mechanism not previously understood.
Professor Petrie theorised 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 does unrepaired.
Although unrepaired DNA is generally harmful-causing tissue to degenerate or develop cancers-it is useful in some parts of the genome, such as those parts resposible for disease defence where variation can help in the resistance to disease. 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.
Using a computer model to map the spread of genes in a population, Professor Petrie demonstrated that the tendency towards reduction in genetic diversity caused by sexual selection is outweighed by the maintenance in greater genetic diversity generated by mutations affecting DNA repair.
The research is published today (28 March 2007) in the academic journal, Heredity, part of the Nature Publishing Group.
Professor Petrie, of the Evolution and Behaviour Research Group in the School of Biology at Newcastle University, said: 'We started this research ten 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.'
In 2005, Professor Petrie and colleagues demonstrated that men with greater genetic diversity in disease defence regions of the genome — and therefore better prospects of passing disease resistance to their offspring — had a number of physical features which women found attractive. The research involved testing men for genetic diversity and showing photographs of them to women, who allocated scores for attractiveness. These scores were found to correlate strongly to genetic diversity.
University of Newcastle upon Tyne
Genetic Diversity Current Events and Genetic Diversity News RSSTwo From One-Pitt Research Maps Out Evolution of Genders From Hermaphroditic Ancestors
Research from the University of Pittsburgh published in the Nov. 20 edition of "Heredity" could finally provide evidence of the first stages of the evolution of separate sexes, a theory that holds that males and females developed from hermaphroditic ancestors.
Study a step toward disease-resistant crops, sustainability
A five-year study that could help increase disease resistance, stress tolerance and plant yields is under way at Purdue University.
Washington University scientists first to sequence genome of cancer patient
For the first time, scientists have decoded the complete DNA of a cancer patient and traced her disease - acute myelogenous leukemia - to its genetic roots.
World's rarest big cat gets a check-up
The world's rarest big cat is alive and well. At least one of them, that is, according to researchers from the Wildlife Conservation Society (WCS) who captured and released a female Far Eastern leopard in Russia last week.
Current mass extinction spurs major study of which plants to save
The Earth is in the midst of the sixth mass extinction of both plants and animals, with nearly 50 percent of all species disappearing, scientists say.
Revealing the evolutionary history of threatened sea turtles
It's confirmed: Even though flatback turtles dine on fish, shrimp, and mollusks, they are closely related to primarily herbivorous green sea turtles.
Scientists propose the creation of a new type of seed bank
While an international seed bank in a Norwegian island has been gathering news about its agricultural collection, a group of U.S. scientists has just published an article outlining a different kind of seed bank, one that proposes the gathering of wild species -- at intervals in the future -- effectively capturing evolution in action.
Scientists decode genome of parasite that causes relapsing malaria
Scientists have deciphered the complete genetic sequence of the parasite Plasmodium vivax, the leading cause of relapsing malaria, and compared it with the genomes of other species of malaria parasites.
Urbanization in Africa at dawn of 20th century marked outbreak of HIV
New research indicates that the most pervasive global strain of HIV began spreading among humans between 1884 and 1924, suggesting that growing urbanization in colonial Africa set the stage for the HIV/AIDS pandemic.
Black-footed ferrets sired by males that died 8 years ago
Two black-footed ferrets at the Smithsonian's National Zoo have each given birth to a kit that was sired by males who died in 1999 and 2000
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