Re: Underestimating 'r'

In article <dhml43$1f57$1@xxxxxxxxxxxxxxxxxxx>,
Tim Tyler <tim@xxxxxxxxxxx> wrote:
>Criticisms of Hamilton's thinking in this group are common - and
>rarely seem to be received very well,

That's because these particular criticisms haven't been very compelling ...

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.
....
>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?
....
>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?

Hamilton's rule can actually be used for group selection as well
as kin selection (maybe for species selection too, though that's
harder to consider).

The r that needs to be used expresses the conditional probability that a
rare allele in an individual also exists in the beneficiary of the behavior,
where these are compared to competitors who don't have the allele (the allele
is rare).

If the behavior is happening within a local population that is partially
inbred, we would have to consider how much more likely the beneficiary is to
have the allele than its competitors in that same population. So if the
selection is individual selection, but the population is partly inbred,
the inbreeding would have to be removed from the conditional probability,
I think.

At any rate this is a real and interesting issue.

Here is one theoretical paper I found in an electronic search, by
Sabin Lessard in Montreal:

Lessard, S., and G. Rocheleau. 2004. Kin selection and coefficients of
relatedness in family-structured populations with inbreeding.
Theoretical Population Biology 66 (4): 287-306.

and others cited by him, by Marcy Uyenoyama at Duke University:

Uyenoyama, M. K. 1984. Inbreeding and the evolution of altruism under kin
selection - effects on relatedness and group-structure. Evolution 38 (4):
778-795.

and even earlier by Mike Wade:

Wade, M. J. and F. Breden. 1981. Effect of inbreeding on the evolution of
altruistic behavior by kin selection. Evolution 35 (5): 844-858.

--
Joe Felsenstein joe@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Department of Genome Sciences and Department of Biology,
University of Washington, Box 357730, Seattle, WA 98195-7730 USA

.

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