Family names are not as strongly correlated with genetics as you might be assuming.

Consider that for each generation the genetics of the family founder are diluted by 50% (assuming that consanguineous relations are excluded). So after 5 generations or so, only ~3% of the heirs' DNA is specific to the family founder.

So, the fact that names per se better predict outcomes than DNA very strongly points to social factors as the major determinants.

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dash2 7 days ago | parent [-]

Unless there's very strong assortative mating...

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pcrh 7 days ago | parent [-]

Wouldn't assortative mating that is sufficiently strong to overcome the 50% dilution per generation amount to consanguinous mating?

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dash2 7 days ago | parent [-]

Not necessarily. You only have to overcome the dilution on specific dimensions. Suppose everyone mates only on intelligence, and marries a person of exactly equal genetic intelligence to themselves. Then there's no dilution per generation on intelligence, though there is on e.g. height.

	▲	pcrh 5 days ago \| parent [-]
		The question here is why names are so highly predictive. It seems highly unlikely that each generation would be selecting on precisely the same genetic features of a particularly prominent family name. This is because that which provides social prominence is not consistent over time.