Human evolution a factor in the rise of disorders

Pressures from evolution may explain the rise of autism, cancer and autoimmune disease. Researchers believe that taking a broader evolutionary perspective to health can reduce suffering and the risk of death.

Evolutionary medicine has pointed out that natural selection favors reproduction over health; biology evolves slower than culture; pathogens evolve more quickly than humans. This assertion, reported in Science Daily, establishes the connection between evolution and sickness, and thus using history and conflicts found in trade-offs in evolution, several explanations can be made as to why some diseases have become prevalent and are now difficult to prevent. Highlights of their findings, also reported in MSNBC, have been published in the journal of Proceedings of the National Academy of Sciences. A summary includes the following: Humans having evolved with parasites and bacteria, had ancestors who developed immunity to "bugs". However, modern hygiene have eliminated many bacteria, including good ones, consequently confusing our immune system to treat all bacteria as foreigners. This "new-found" hypersensitivity can explain allergies, asthma and autoimmune disease Cancer is more prevalent in humans than other species because of an inability to adapt to modern societal risks. The introduction of tobacco, alcohol, high-fat diet and contraceptives have become risk factors that affect the modern human. Culture and new family systems (the existence of "non-traditional" or non nuclear family structures) could explain autism and schizophrenia. Autism, a disorder that reveals itself in child development, may be a consequence of a genetic battle of the sexes. Maternal and paternal genes fight whereby one will overtake the other. This idea is an extension of an evolutionary conflict that finds the mother's genes dedicating all resources to her children and a father's gene's only wanting to invest in his biological kids (not offspring from another male). If a paternal gene is expressed in certain chromosomes, the outcome can negatively affect child behavior and development. In contrast, other psychoses can be found if maternal genes are expressed.