Perplexed in Peoria wrote:
> "Anon."  wrote
in message
> news:cav343$tgj$1{at}darwin.ediacara.org...
> 
>>As for epistasis, if something isn't heritable, then it can't be
>>inherited.  Genetic epistatic effects can be inherited (because groups
>>of genes can be inherited together), and hence does not come under what
>>I was suggesting.
> 
> 
> Pardon me for butting in, but some time ago I told John that the
> reason that non-additive epistatic effects are usually omitted
> from evolutionary models is that such effects are not effectively
> heritable.  Was this incorrect?
> 
Yes this was - the effects can be inherited, but the strength of 
directional selection is not affected by the non-additive epistatic effects.

This will be explained in Vol. 2 of Lynch & Walsh, if it is ever 
published.  But some of the material is here:
http://nitro.biosci.arizona.edu/zbook/volume_2/vol2.html>

> In saying this, I had in mind the situation in which the two loci
> are on different chromosomes.  I (and John, I think) realize that
> there is some heritability  when the loci are in the same linkage
> group, but it seems to me that weak linkage cannot be a factor
> in long term evolution.  Strong linkage, of course, might be a
> factor, but this doesn't argue against the adequacy of the models
> because a strongly linked cluster of loci can be treated as a
> single "super-gene" in the additive models.
> 
The additive by additive component of variation does have an effect on 
selection, but it is transient.  See Chapter 4 of Lynch & Walsh on the 
web page above.

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
---
þ RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info{at}bbsworld.com

---
 * RIMEGate(tm)V10.2áÿ* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 6/19/04 10:17:28 PM