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Mutation: Difference between revisions
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Some evidence suggests that there are more people with deleterious mutations in the human population due to a number of factors, including but not limited to: milder ecological conditions, modern medicine,<ref>https://www.ncbi.nlm.nih.gov/pubmed/9371795/</ref> advanced paternal age<ref>https://www.spectrumnews.org/news/parental-age-different-impact-autism-schizophrenia/</ref> and especially due to much lower infant mortality.<ref>https://doi.org10.1007/s40806-017-0084-x</ref> | Some evidence suggests that there are more people with deleterious mutations in the human population due to a number of factors, including but not limited to: milder ecological conditions, modern medicine,<ref>https://www.ncbi.nlm.nih.gov/pubmed/9371795/</ref> advanced paternal age<ref>https://www.spectrumnews.org/news/parental-age-different-impact-autism-schizophrenia/</ref> and especially due to much lower infant mortality.<ref>https://doi.org10.1007/s40806-017-0084-x</ref> | ||
Given the complex nature and function of the human brain, one would expect it to be particularly vulnerable to deleterious mutations,<ref>https://www.ncbi.nlm.nih.gov/pubmed/23153596/</ref> which may be reflected in the apparent rise in the prevalence of Autism Spectrum Disorders, as it has been argued that up to 30% of cases of this condition in simplex families (where only one member has the condition) could be attributed to ''de novo'' mutations.<ref>https://www.ncbi.nlm.nih.gov/pubmed/26401017/</ref> | Given the complex nature and function of the human brain, one would expect it to be particularly vulnerable to deleterious mutations,<ref>https://www.ncbi.nlm.nih.gov/pubmed/23153596/</ref> which may be reflected in the apparent rise in the prevalence of Autism Spectrum Disorders, as it has been argued that up to 30% of cases of this condition in simplex families (where only one member has the condition) could be attributed to ''de novo'' mutations.<ref>https://www.ncbi.nlm.nih.gov/pubmed/26401017/</ref> | ||
Extrapolation of the rate of deleterious mutational load in mice and other organisms has led to a rough estimate of a 1% decline in the baseline physical and mental performance attributes of populations in conditions of extreme relaxed selection pressures (both natural and sexual) per generation. This estimate may be overly conservative, however, particularly in regards to brain function.<ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4788123/#bib64</ref> Some researchers have also argued factors that decrease deleterious mutational load in populations, such as reductions in the rate of [[inbreeding depression|inbreeding]] and pre-natal therapeutic fetus selection (the abortion of offspring with severe abnormalities revealed through pre-birth screening) may serve to counteract these effects somewhat.<ref>https://www.researchgate.net/publication/323320480_Relaxed_selection_and_mutation_accumulation_are_best_studied_empirically_Reply_to_Woodley_of_Menie_et_al</ref> | Extrapolation of the rate of deleterious mutational load in mice and other organisms has led to a rough estimate of a 1% decline in the baseline physical and mental performance attributes of populations in conditions of extreme relaxed selection pressures (both natural and sexual) per generation. This estimate may be overly conservative, however, particularly in regards to brain function. | ||
In terms of human intelligence and mental function, it has been asserted that [[IQ|general intelligence]] has declined due to increasing mutational load in the human genome, though deleterious mutations appear to only account for up to 7% of the secular decline in general intellgence. Other factors, such as a general negative correlation between intelligence and fertility and increases in neurotoxins that disrupt brain function and development more to blame for this apparent decline in general intelligence, independent of secular increases in IQ test scores due to the [https://en.wikipedia.org/wiki/Flynn_effect Flynn Effect].<ref>https://www.sciencedirect.com/science/article/abs/pii/S0191886915301161</ref> | |||
<ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4788123/#bib64</ref> Some researchers have also argued factors that decrease deleterious mutational load in populations, such as reductions in the rate of [[inbreeding depression|inbreeding]] and pre-natal therapeutic fetus selection (the abortion of offspring with severe abnormalities revealed through pre-birth screening) may serve to counteract these effects somewhat.<ref>https://www.researchgate.net/publication/323320480_Relaxed_selection_and_mutation_accumulation_are_best_studied_empirically_Reply_to_Woodley_of_Menie_et_al</ref> | |||
Mutational load may not be related to economic status very much. On the one hand, less mutated individuals are expected to rise higher in the socioeconomic hierarchy. On the other hand, the elite has a slightly lower infant mortality rates, milder living conditions and sometimes engages in excessive inbreeding, which may lead to the lower classes (who had been under conditions of Darwinian selection for longer, due to their lower standard of living) to be less mutated. Also, higher mutational load is only weakly related to certain traits important for socioeconomic success, such as general intelligence,<ref>https://www.sciencedirect.com/science/article/abs/pii/S0191886915301161</ref> so one would expect that a lot of these highly mutated individuals would still be able to attain positions of social and economic influence. | Mutational load may not be related to economic status very much. On the one hand, less mutated individuals are expected to rise higher in the socioeconomic hierarchy. On the other hand, the elite has a slightly lower infant mortality rates, milder living conditions and sometimes engages in excessive inbreeding, which may lead to the lower classes (who had been under conditions of Darwinian selection for longer, due to their lower standard of living) to be less mutated. Also, higher mutational load is only weakly related to certain traits important for socioeconomic success, such as general intelligence,<ref>https://www.sciencedirect.com/science/article/abs/pii/S0191886915301161</ref> so one would expect that a lot of these highly mutated individuals would still be able to attain positions of social and economic influence. | ||