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[[File:Infant_Mortality_Rate_by_Region_1950-2050.png|thumb|Human evolution is attuned for a ~100x higher selection pressure ruling out most deleterious mutations at young age]] | [[File:Infant_Mortality_Rate_by_Region_1950-2050.png|thumb|Human evolution is attuned for a ~100x higher selection pressure ruling out most deleterious mutations at young age]] | ||
A genetic '''mutation''' occurs when mistakes are made during copying/[[reproductive success|reproduction]] of genetic code. | A [[Genetics|genetic]] '''mutation''' occurs when mistakes are made during copying/[[reproductive success|reproduction]] of genetic code. | ||
Mutations may be beneficial, neutral or deleterious (bad) for the organism. Around 95% of mutations have no significant immediate effect or are neutral, and most remaining ones are deleterious.<ref>http://www.cs.unc.edu/~plaisted/ce/genetics.html</ref><ref>http://www.talkorigins.org/faqs/mutations.html#Q1</ref> Mutations are unavoidable and they are necessary for [[evolution]] to work at all. Natural and [[sexual selection]] decide which phenotypes will be prevalent in future generations and which mutations will become fixed (meaning highly prevalent in the gene pool). | Mutations may be beneficial, neutral or deleterious (bad) for the organism. Around 95% of mutations have no significant immediate effect or are neutral, and most remaining ones are deleterious.<ref>http://www.cs.unc.edu/~plaisted/ce/genetics.html</ref><ref>http://www.talkorigins.org/faqs/mutations.html#Q1</ref> Mutations are unavoidable and they are necessary for [[evolution]] to work at all. Natural and [[sexual selection]] decide which phenotypes will be prevalent in future generations and which mutations will become fixed (meaning highly prevalent in the gene pool). | ||
Older parents produce more mutations in their offspring.<ref>https://www.bionews.org.uk/page_96182</ref> There is also evidence that the mutation rate is much higher in human males (up to 6 times higher), which has also been found in other species such as birds.<ref>https://www.ncbi.nlm.nih.gov/pubmed/10978293</ref><ref>https://www.sciencedirect.com/science/article/pii/S0959437X02003544?via%3Dihub</ref> This has lead to a hypothesis of evolution being largely driven by mutations in the male germline. This finding is heavily contested, however. | Older parents produce more mutations in their offspring.<ref>https://www.bionews.org.uk/page_96182</ref> There is also evidence that the mutation rate is much higher in [[Men|human males]] (up to 6 times higher), which has also been found in other species such as birds.<ref>https://www.ncbi.nlm.nih.gov/pubmed/10978293</ref><ref>https://www.sciencedirect.com/science/article/pii/S0959437X02003544?via%3Dihub</ref> This has lead to a hypothesis of evolution being largely driven by mutations in the male germline. This finding is heavily contested, however. | ||
Massively reduced infant mortality may be the main driver of a recent increase in overall mutational load, leading to a higher incidence rate of disease, autism, obesity, sinistrality (left-handedness), asymmetry etc. | Massively reduced infant mortality may be the main driver of a recent increase in overall mutational load, leading to a higher incidence rate of disease, [[Asperger's syndrome|autism]], obesity, sinistrality (left-handedness), asymmetry etc. | ||
== Kinds of mutations that can occur == | == Kinds of mutations that can occur == | ||
{{See also|{{W|Epistasis}}, and [[Social epistasis amplification model]]}} | {{See also|{{W|Epistasis}}, and [[Social epistasis amplification model]]}} | ||
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== Rise in mutations == | == Rise in mutations == | ||
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> Due to the economic cost associated with a degraded gene pool, the [[wikipedia:demographic transition|demographic transition]] can be considered an instance of the [[wikipedia:tragedy of the commons|tragedy of the commons]] as the externalities of the degraded gene pool are foisted off on future generations at the benefit of avoiding the near-term costs of having women birth many children (rather than work) and the cost of a high mortality selection pressure on the offspring. | 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> Due to the economic cost associated with a degraded gene pool, the [[wikipedia:demographic transition|demographic transition]] can be considered an instance of the [[wikipedia:tragedy of the commons|tragedy of the commons]] as the externalities of the degraded gene pool are foisted off on future generations at the benefit of avoiding the near-term costs of having [[Femoid|women]] birth many children (rather than work) and the cost of a high mortality selection pressure on the offspring. | ||
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> | ||