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R. A. Palacios A. D. Burghardt J. T. Frías-Hernández V. Olalde-Portugal N. Grados L. Alban O. Martínez-de la Vega 《Plant Systematics and Evolution》2012,298(1):165-171
The problems of delimitation of species of Prosopis originate from the few morphological discontinuities which exist among some of them; some, however, originated as a result
of wide distribution of germplasm without proper knowledge of the species, in particular, much material catalogued as P. juliflora, but being of other species, was distributed for reforestation projects worldwide. This work tests the morphological results
obtained for P. pallida and P. limensis of the Peruvian–Ecuadorian coast and for P. juliflora of the Caribbean Basin of Colombia and Venezuela utilizing a study of AFLPs and a study of the morphology of plantlets developed
in a conventional garden study. The phenogram obtained for the AFLPs demonstrates each of the three species to be a well differentiated
cluster and the molecular variance between them is significantly greater than the variance within each species. Study of the
plantlets also indicates statistically significant differences for four morphological characters between P. juliflora and the other two species (P. pallida and P. limensis). These results, in addition to the morphological differentiation evident between adult plants of P. pallida and P. limensis and the clear separation of these two species from P. juliflora, corroborate the genetic identity of the three taxa analyzed. 相似文献
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Bart Lievens Peter van Baarlen Stefan van Kerckhove Martijn Rep 《Mycological Research》2009,113(10):1181-1191
Fusarium oxysporum is a ubiquitous species complex of soilborne plant pathogens that comprises many different formae speciales, each characterized by a high degree of host specificity. In this study, the evolutionary relationships between different isolates of the F. oxysporum species complex have been examined, with a special emphasis on the formae speciales lycopersici and radicis-lycopersici, sharing tomato as host while causing different symptoms. Phylogenetic analyses of partial sequences of a housekeeping gene, the elongation factor-1α (EF-1α) gene, and a gene encoding a pathogenicity trait, the exopolygalacturonase (pgx4) gene, were conducted on a worldwide collection of F. oxysporum strains representing the most frequently observed vegetative compatibility groups of these formae speciales. Based on the reconstructed phylogenies, multiple evolutionary lineages were found for both formae speciales. However, different tree topologies and statistical parameters were obtained for the cladograms as several strains switched from one cluster to another depending on the locus that was used to infer the phylogeny. In addition, mating type analysis showed a mixed distribution of the MAT1-1 and MAT1-2 alleles in the F. oxysporum species complex, irrespective of the geographic origin of the tested isolates. This observation, as well as the topological conflicts that were detected between EF-1α and pgx4, are discussed in relation to the evolutionary history of the F. oxysporum species complex. 相似文献
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The method of polymerase chain reaction with random primers (RAPD PCR) was used to identify the progeny of the crosses between
three sturgeon species, Amur sturgeon (Acipenser schrenckii Brandt, 1869), Siberian sturgeon (A. baerii Brandt, 1869), and sterlet (A. ruthenus Linnaeus, 1758). Using ten primers, genetic variation in 70 yearlings, produced in seven individual crosses: Acipenser schrenckii × A. schrenckii, A. baerii × A. baerii, A. ruthenus × A. ruthenus, A. schrenckii × A. baerii, A. baerii × A. schrenckii, A. schrenckii × A. ruthenus, and A. ruthenus × A. schrenckii was described and evaluated. It was demonstrated that the samples composed of hybrids from individual crosses were more variable
than the samples of parental species. On the other hand, pooled samples of hybrids from two cross directions were genetically
less variable than the pooled samples of their parents. The three main features of the hybrid RAPD profiles identified included:
(1) preservation of marker DNA fragments of both parents in one genome; (2) presence of specific DNA fragments, absent from
both parents; and (3) dependence of the frequency of some DNA fragments from the cross direction. Multidimensional scaling
clearly distinguishes in the space of three coordinates the individuals of original species and the hybrid progeny with differentiation
in the groups of direct and backcross hybrids. Analysis of relationships (UPGMA and NJ) pointed to substantial differentiation
between the species, as well as between the species and hybrid progeny. Close genetic relationships between direct and backcross
hybrids were demonstrated. Multilocus RAPD markers in association with statistical methods are considered to be the useful
tool for discrimination of interspecific hybrids of sturgeon. Possible reasons for the differences in the hybrid RAPD profiles
are discussed.
Original Russian Text ? K.V. Rozhkovan, G.N. Chelomina, E.I. Rachek, 2008, published in Genetika, 2008, Vol. 44, No. 11, pp.
1453–1460. 相似文献