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Genetic Diversity and the Reproductive System in Related Species of Antirrhinum

Annals of botany 2006 v.98 no.5 pp. 1053-1060
outbreeding, loci, geographical variation, inbreeding, gene flow, plant reproduction, genetic relationships, genetic variation, allozymes, Antirrhinum majus, France, Israel, Portugal, Spain
BACKGROUND: and Aims Seven related species of Antirrhinum (A. siculum, A. majus, A. latifolium, A. linkianum, A. litigiosum, A. cirrhigherum and A. tortuosum) were studied in order to compare levels of genetic variation and its partitioning in them, and to check relationships between genetic patterns and the reproductive system. METHODS: Eight hundred and fifty-one plants were screened for variability at 13 allozyme loci by means of horizontal starch gel electrophoresis. Parameters of genetic diversity and its partitioning, the inbreeding coefficient as well as an indirect estimate of gene flow based on the equation: Nm = (1 - GST)/4GST, were calculated. Key Results Genetic variability in A. siculum was found to be the lowest known in the genus. Mean values of FIT and FIS were mostly positive and not significantly different from zero. Population differentiation (FST) ranged between 6·1 in A. tortuosum and 17·6 in A. linkianum. The inbreeding coefficient within populations ranged between FIS = -0·5 in A. tortuosum and FIS = 1 in A. siculum. Estimates of gene flow ranged between Nm = 15 in A. majus (considered as very high) to Nm = 0·42 in A. siculum (considered as low). CONCLUSIONS: Correlation was found between levels of diversity and differentiation on one hand, and the reproductive system of the studied taxa on the other. Striking differences among species in the inbreeding coefficient (FIS) show different reproductive systems, which mostly support previous reports. Strategies for the conservation of A. siculum are recommended, such as preservation of natural populations as well as ex situ preservation of seeds from different populations.