The number, age, sharing and relatedness of S-locus specificities in Prunus

• Tipo: Artigo em Revista Científica Internacional
• Data: 2008

Autores

Vieira, J (Autor) Outra; Nuno A Fonseca (Autor) Outra; Santos, RAM (Autor) Outra; Habu, T (Autor) Outra; Tao, R (Autor) Outra; Cristina Vieira (Autor) Outra

Revista

Título: Genetics Research

Vol. 90

Páginas: 17-26

ISSN: 0016-6723

Indexação

ISI Web of Knowledge - 15 Citações

Scopus - 14 Citações

Outras Informações

ID Authenticus: P-004-1R2

DOI: 10.1017/s0016672307009044

Abstract (EN): In gametophytic self-incompatibility systems, many specificities (different 'lock-and-key' combinations) are maintained by frequency-dependent selection for very long evolutionary times. In Solanaceae, trans-specific evolution (the observation that an allele from one species may be more closely related to an allele from another species than to others from the same species) has been taken as an argument for the very old age of specificities. In this work, by determining, for the first time, the age of extant Prunus species, we show that this reasoning cannot be applied to Prunoideae. Furthermore, since our sample size is large (all S-RNase encoding the female component and SFB encoding the male component GenBank sequences), we were able to estimate the age of the oldest Prunus specificities. By doing so, we show that the lower variability levels at the Prunus S-locus, in comparison with Solanaceae, is due to the younger age of Prunus alleles, and not to a difference in silent mutation rates. We show that the ancestor to extant Prunus species harboured at least 102 specificities, in contrast to the maximum of 33 observed in extant Prunus species. Since the number of specificities that can be maintained in a population depends on the effective population size, this observation suggests a bottleneck in Prunus evolutionary history. Loss of specificities may have occurred during this event. Using only information on amino acid sites that determine specificity differences, and a simulation approach, we show that a model that assumes closely related specificities are not preferentially lost during evolution, fails to predict the observed degree of specificity relatedness.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10