# how many nations can a nation contain?

m.g. miles considers the question in “Chalk and cheese.”

highly recommended! (^_^)

Re. the Cafalli-Sforza inbreeding numbers: I’d love to do the calculations and fill out that map with all the regions. Did you calculate based on the numbers given here? Those charts give four different levels of inbreeding (Uncle-niece/aunt-nephew, First cousins, First cousins once removed, Second cousins); do you remember which ones you used?

2. @m.g. – “Did you calculate based on the numbers given here? Those charts give four different levels of inbreeding (Uncle-niece/aunt-nephew, First cousins, First cousins once removed, Second cousins); do you remember which ones you used?”

yes, those are the numbers i used (@the link in your comment). i only used the numbers for first-cousin marriages. that was because i wanted to compare all regions in italy and there’s only numbers for first-cousin marriages in sicily, so i cut out the other marriages in the other regions. (see this post.)

it would be cool to see a map with all the regions included! unfortunately, some of the regions — take frosinone in lazio, for example — don’t have any numbers going back to 1910. that’s why there were gaps in my data — i wanted to compare the earliest period (1910-1914) with the latest (1960-1964), so some regions were left out in my chart. you could easily do a map with all the regions from, say, the 1930-34 period, or any of the other periods up to and including 1960-64.

buona fortuna! (^_^)

3. At what point does out-breeding damage one’s inclusive fitness beyond any gains that could be achieved?

As Frank Salter notes (using Cafalli-Sforza’s numbers):

“For a person of English ethnicity, choosing an English spouse over a Dane gains less than one percent fitness. But choosing an English spouse over a Bantu, one yields a fitness gain of 92 percent…. The same applies in reverse order, so that a Bantu who chooses another Bantu instead of someone of English ethnicity has 92% more of his or her genes in offspring as a result. It is almost the equivalent to having twice the number of children with an English spouse. Thus assortative mating by ethnicity can have large fitness benefits, the largest derived from choosing mates within geographic races.”

http://sociobiologicalmusings.blogspot.com/2011/10/problems-with-mixed-race-marriages-and.html

4. @reader – “At what point does out-breeding damage one’s inclusive fitness beyond any gains that could be achieved?”

yes, a good and important question, reader.

note, tho, that what i am (mostly) discussing on this blog are inbreeding and outbreeding levels within a population. i’m interested in how those affect the social behaviors within a society.

what you bring up is also, of course, interesting and important. not exactly what i’m talking about, tho.

5. “m.g. miles considers the question in “Chalk and cheese.””

good stuff

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“At what point does out-breeding damage one’s inclusive fitness beyond any gains that could be achieved?”

I think it will be at the point of maximum trust which i believe will be at the point of maximum relatedness defined…i’m not a statistician so i’m not quite sure of the correct terminology… but something to do with minimizing average genetic distance – variance?

The way i visuallize it is to imagine a nation of genetically identical clones. The average genetic distance between individuals would be zero and us really would mean us. I think the optimum case would be the closest you could get to that naturally without cloning. If you’re moving towards maximum trust you’ll be increasing fitness. If you’re moving away from that point you’ll be reducing fitness.

Out-breeding *within* a nation increases total relatedness expressed in this way because what it does is average out the effects of regional and local inbreeding.

If two populations were both at the same state of homogeny-exogamy then they could possibly merge with no loss of fitness and gain increased synergy e.g. English and Dutch in North America.

I think there will be a very simple mathematical way of expressing this concept because at the root is a very simple geometric relationship i.e. two parents, four grand-parents, eight grand-parents etc and the trust breaks down rapidly with genetic distance i.e. it’s the degree of difference that is the key not the degree of similarity.

5% different matters more than 95% the same.