[asa] Recent MHC Study

From: David Opderbeck <dopderbeck@gmail.com>
Date: Thu Oct 25 2007 - 13:01:23 EDT

Does anyone know whether this study has any possible significance to the MHC
"bottleneck" problem?

*

RAPID EVOLUTION OF MHC CLASS I GENES IN PRIMATES GENERATES NEW DISEASE
ALLELES IN MAN VIA HITCHHIKING DIVERSITY, Genetics (2006): *
http://www.genetics.org/cgi/rapidpdf/genetics.106.057034v1

which makes the following observation:

In summary, we demonstrate that the MHC-I diversity is not limited to the
antigen/TCR binding sites but spreads to surrounding segments. Corroborating
data suggests that this hitchhiking diversity, otherwise eliminated by
purifying selection in most other genomic sites, has perdured within the MHC
perhaps because of the strong biological incentive for constant generation
and maintenance of a species-specific diverse allelic repertoire (H ILL *et
al. *1991; KIEPIELA *et al. *2004).

 This was evidenced by the existence of a large reservoir of hvSNV,
reminiscent of the fact that most of MHC diversity is *de novo *generated
and not as the result of their trans-species inheritance as initially
thought (F IGUEROA *et al. *1988; LAWLOR *et al. *1988). This result finally
puts the MHC in line with the bulk of population and evolutionary genetics
data which firmly conclude that a narrow bottleneck has occurred at the
origin of our species (CANN *et al. *1987; H AMMER 1995), a fact
inconsistent with massive flow of alleles from one species to the next as
required by the transspecies postulate (AYALA *et al. *1994). Moreover, this
fitness in fighting infections seems to have taken its toll on neighboring
loci, as the most gene-rich and polymorphic segment around *HLA-B *is also
where most MHC-I diseases are mapped to. Finally, this observation is not
limited to the MHC class I region as it extends to the other MHC-disease
associations and perhaps to the wider genome.

To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Thu Oct 25 13:02:48 2007

This archive was generated by hypermail 2.1.8 : Thu Oct 25 2007 - 13:02:48 EDT