Underestimating 'r'

Criticisms of Hamilton's thinking in this group are common - and
rarely seem to be received very well, so it's with some hesitation
that I post on a related subject.

One of the fairer criticisms of Hamilton's thinking I've seen here
is the idea that "r" is being consistently under estimated.

It's common to calculate "r" by using a truncated family tree - and
ignore relationships between great grandparents as being of low
relevance.

Such truncated trees tend to give lower values for relatedness
than using a full tree would give.

How much lower is a question difficult question. If calculating
relatedness using hamming distnaces, the figure depends to some extent on
the size of the units being compared - and how close a match is needed
before two units are described as being related.

Also, the figures may be significantly different for groups of organisms
like cheetahs (an inbred group) and mice (an outbred one).

If "r" between organisms in a group or species is *actually* higher
than is commonly belived, that might contribute to group/species-level
selection - the extent of the power of which is still the subject
of some controversy and debate.

Hamilton's rule talks about the circumstances under which a trait
will spread through a population - but it doesn't itself consider
the possibility of populations competing with one another - and the
possibilty of high level selection trumping the effects of low-level
selection.

So - is "r" higher than convention would dictate; and if so - how
much higher? Evidence I've previously posted relating to the
frequency of SNPs (and other polymorphisms) suggests to me that
it is higher - and significantly so - perhaps enough to make me
70% related to my mother - rather than the 50% convention
dictates - and enough to make individuals quite a bit more
than 0% related to other "unrelated" members of the population.

If so, what's the practical effect of this? As far as I can
tell, the effect would be pretty limited. It ought to make
individuals behave somewhat altruistically to other members
of their species. However there are a raft of other theories
that predict this sort of thing (e.g. reciprocal altruism) -
so the effect may be hard to tease out. It wouldn't make
*much* difference to how relatives are treated - since
their relative relatednesses would remain pretty much
the same.

Any comments about all this? What's your personal estimate
of "r" between, say, randomly-selected humans? If r /is/
being frequently underestimated, what empirical test would
throw the most light on the issue?
--
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Relevant Pages

  • Re: Underestimating r
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  • Re: Underestimating r
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  • Re: Underestimating r
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