Originally published as Genetics Published Articles Ahead of Print on August 30, 2008.

Genetics, Vol. 180, 483-491, September 2008, Copyright © 2008
doi:10.1534/genetics.108.087825

Recombination at Prunus S-Locus Region SLFL1 Gene

Jorge Vieira, Eliana Teles, Raquel A. M. Santos and Cristina P. Vieira1

Instituto de Biologia Celular e Molecular (IBMC), University of Porto, 4150-180 Porto, Portugal

1 Corresponding author: IBMC, Molecular Evolution, Group Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
E-mail: cgvieira{at}ibmc.up.pt

In Prunus, the self-incompatibility (S-) locus region is <70 kb. Two genes—the S-RNase, which encodes the functional female recognition component, and the SFB gene, which encodes the pollen recognition component—must co-evolve as a genetic unit to maintain functional incompatibility. Therefore, recombination must be severely repressed at the S-locus. Levels of recombination at genes in the vicinity of the S-locus have not yet been rigorously tested; thus it is unknown whether recombination is also severely repressed at these loci. In this work, we looked at variability levels and patterns at the Prunus spinosa SLFL1 gene, which is physically close to the S-RNase gene. Our results suggest that the recombination level increases near the SLFL1 coding region. These findings are discussed in the context of theoretical models predicting an effect of linked weakly deleterious mutations on the relatedness of S-locus specificities. Moreover, we show that SLFL1 belongs to a gene family of at least five functional genes and that SLFL1 pseudogenes are frequently found in the S-locus region.