A complex selection signature at the human AVPR1B gene.
BACKGROUND
The vasopressin receptor type 1b (AVPR1B) is mainly expressed by pituitary corticotropes and it mediates the stimulatory effects of AVP on ACTH release; common AVPR1B haplotypes have been involved in mood and anxiety disorders in humans, while rodents lacking a functional receptor gene display behavioral defects and altered stress responses.


RESULTS
Here we have analyzed the two exons of the gene and the data we present suggest that AVPR1B has been subjected to natural selection in humans. In particular, analysis of exon 2 strongly suggests the action of balancing selection in African populations and Europeans: the region displays high nucleotide diversity, an excess of intermediate-frequency alleles, a higher level of within-species diversity compared to interspecific divergence and a genealogy with common haplotypes separated by deep branches. This relatively unambiguous situation coexists with unusual features across exon 1, raising the possibility that a nonsynonymous variant (Gly191Arg) in this region has been subjected to directional selection.


CONCLUSIONS
Although the underlying selective pressure(s) remains to be identified, we consider this to be among the first documented examples of a gene involved in mood disorders and subjected to natural selection in humans; this observation might add support to the long-debated idea that depression/low mood might have played an adaptive role during human evolution.
Cagliani
Rachele
R
Scientific Institute IRCCS E, Medea, Bioinformatic Lab, Bosisio Parini, LC, Italy. rachele.cagliani@bp.lnf.it
Fumagalli
Matteo
M
Pozzoli
Uberto
U
Riva
Stefania
S
Cereda
Matteo
M
Comi
Giacomo P
GP
Pattini
Linda
L
Bresolin
Nereo
N
Sironi
Manuela
M
D000818:Animals; D044383:Black People / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D019964:Mood Disorders / Q000235:genetics; D010802:Phylogeny; D017483:Receptors, Vasopressin / Q000235:genetics*; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D044465:White People / Q000235:genetics
D017483:Receptors, Vasopressin