rationalskepticism.org

Greg the Grouper wrote:So in an evolutionary sense, one might consider the result of a mutation to be a 'genetic disorder' due to the affect that a mutation would have on a DNA sequence, regardless of the resulting phenotype? Am I understanding that correctly?

Disorder tends to have a negative meaning, but if a disordering gives a fitness advantage then it a reproduction benefit for the organism. The example of sickle cell anaemia given by Hack is an interesting one. This disorder would normally have been eliminated from the genepool as it gave serious disadvantage to individuals with it except that it wasn't because this disorder gave a sufficient degree of protection from a parasitic disease (Malaria) to overcome the disadvantage it gave, making it so common that it continues even without the presence of the threat of malaria. NB the disadvantage of this is most clearly apparent when an individual carries two copies of the gene. https://en.wikipedia.org/wiki/Sickle_cell_disease
But this is a well known example of a successful genetic disorder, successful as it was able to successfully reproduce despite the significant disadvantage it caused by giving another separate advantage.