Plastid and mitochondrial DNAs from Hedysarum species of the western Mediterranean basin, H. spinosissimum ssp eu-spinosissimum, H. spinosissimum ssp capitatum, H. carnosum, H. coronarium and H. flexuosum, were compared by restriction endonuclease fragment analysis. ctDNA fragment patterns for ssp eu-spinosissimum and ssp capitatum were indistinguishable in different enzyme digests. An identical ctDNA variation was found in Hpa II digests with two Sardinian populations of ssp capitatum. Each of the two subspecies was characterized by specific mt DNA patterns with Pst I, Bam HI, Sma I and EcoRI. No variation was detected in populations of different geographical origins for a given subspecies. H. carnosum, H. coronarium and H. flexuosum generated specific ct and mt DNA patterns. Comparison of mitochondrial fragments indicated: - a strong homology between the two subspecies, - a closer homology among the three other diploids, each being closer to the other two than to H. spinosissimum subspecies - as was also the case for the plastid genomes.
Several samples of wild populations of two subspecies of the genus Hedysarum (H. spinosissimum subspecies capitatum, an outcrosser, and H. spinosissimum subspecies euspinosissimum, a selfer) were examined with respect to variability of 25 quantitative characters and allozyme variation at 13 loci. The amount of phenotypic and genetic variation within and among populations was documented. For most of the 25 quantitative characters, the differences between population means and between the total variances of the populations were higher in the selfer than in the outbreeder. Significant among-population genetic variation was found for nearly all characters in the two subspecies, but the outbreeder had higher within-population variability than the selfer with heterogeneity among characters. However, allozyme variation at 13 loci in about the same number of populations showed higher levels of genetic variability in the outcrossing subspecies capitatum compared with the selfing subspecies euspinosissimum, based on measures of mean number of alleles per locus, mean proportion of polymorphic loci, and mean heterozygosity. Therefore, H. spinosissimum subsp. capitatum appeared to be highly polymorphic in contrast to the greater monomorphism within populations of H. spinosissimum subsp. euspinosissimum. The genetic affinities of different populations of a subspecies are uniformly high, with Nei's genetic identity ranging from 0.983 to 0.997 in the selfing subspecies euspinosissimum and from 0.922 to 1.000 in the outcrossing subspecies capitatum.Key words: Hedysarum, genetic variation, populations, electrophoresis.
Summary
Baatout, H.; Marrakchi, M. & Combes, D.: Genetic divergence and allozyme variation within and among populations of Hedysarum spinosissimum subsp. capitatum and subsp. spinosissimum (Papilionaceae). ‐ Taxon 40: 239–252. 1991. ‐ ISSN 0040‐0262.
Three outcrossing populations of Hedysarum spinosissimum subsp. capitatum and two self‐pollinating populations of H. spinosissimum subsp. spinosissimum were surveyed for variation at 36 allozyme loci. The proportion of polymorphic loci ranged from 25.0 to 75.0 % in subsp. capitatum and from 27.8 to 30.6 % in subsp. spinosissimum, and the mean heterozygosity from 0.088 to 0.299 in subsp. capitatum and from 0.086 to 0.097 in subsp. spinosissimum. No karyotypic differences distinguish the two subspecies, and no hybridization between the allogamous H. spinosissimum subsp. capitatum and the autogamous subsp. spinosissimum was noted. Allele frequency differences between the two subspecies indicate that they are clearly distinct in several genes coding for the enzymes peroxidase, esterase and acid phosphatase. The level of genetic divergence at the enzyme level, revealed by electrophoretic analysis of the two taxa, supports their specific distinctness, the mean genetic distance between them being 0.45 ‐ which is indicative of a long period of lack of gene flow between them.
The taxonomic status of the species complex Hedysarum spinosissimum L. (s.l.) has been evaluated on the basis of the phenetic variation within and between populations. Twenty-five characters were measured on plants grown from seeds of 9 populations of H. spinosissimum ssp. capitatum and 12 populations of H. spinosissimum ssp. spinosissimum from the western Mediterranean basin. Data were analyzed by means of multivariate methods. Stepwise discriminant analysis led to conclusions similar to those derived from principal components analysis. The results are discussed from a systematic point of view. On the basis of vegetative and floral characters, numerical analyses supported two morphologically distinct groups of operational taxonomic units corresponding to the predominantly selfing H. spinosissimum and the mostly outcrossing H. capitatum. Key words: Hedysarum spinosissimum L., phenetic variation, morphological contrast, Mediterranean basin, multivariate analysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.