the thread I was replying to so I'm just going to dump this here because I typed the thing out and I'll be damned if I'm going to just delet it
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>>12435226inbreeding can be bad mostly due to what's iss known as inbreeding depressionm which is generally caused deleterious recessive mutations but if you inbreed for long enough you can remove many of these deleterious alleles through what is kown as purging.
the second major downside to inbreeding is reducing the adaptive capability of the population to changing conditionsthis is the more serious factor long term so is generally combatted through some level of outbreeding and introgression
the major positive of inbreeding is from building up com,plimentary gene structures and refining their configuration
the dangers of outbreeding mainly deal with the same factors but in reverse
very little ability to develop complimentary gene structures if you're constantly resetting the system
potentially there are more adaptations floating around so in the event of sudden shifts in conditions there is more flexibility
homozygous recessive mutations become increasingly rare so the chances of them causing disease is much reduced however this can mask an ever increasing mutational load because these recessives are being purged
as you can see it's a complex issue but there can be considered to be an optimal level that balances the two sides
there was an icelandic paper that looked into mariages, birthrates and mortality over about 200 years that found marriages between 3rd-4th cousins tended to produce the most kids that went on to have their own families
http://facelab.org/debruine/Teaching/EvPsych/files/Helgason_2008.pdfAnthropologist Robin Fox also has very interesting research
http://robin-fox.com/endogamy = in
exogamy = out
mediogamy = intermediate
