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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters A 34 (1971), S. 102-103 
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1986), S. 88-93 
    ISSN: 1432-2242
    Keywords: Parent-offspring regression ; Multivariate analysis ; Cluster analysis ; Principal component analysis ; Clarkia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Interspecific heritability values were estimated using parent-offspring regression analyses for 11 morphological traits differentiating Clarkia nitens and C. speciosa subsp. polyantha. Estimates ranged from near 0 for anther color and germination percentage, to 0.8 for calyx length and petal tip color. Phenotypic, genetic, and environmental correlation matrices were computed to determine the extent of interspecific correlations of traits. Cluster analyses of the genetic and environmental correlation matrices each resulted in three clusters of correlated traits; however, the clusters derived from the two matrices were different. The clusters produced by analysis of the environmental correlation matrix were similar to the factors obtained from principal component analysis of the phenotypic correlation matrix. Genetic correlations may result from strong linkage due to interspecific chromosomal differences.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 87 (1994), S. 773-781 
    ISSN: 1432-2242
    Keywords: Lens culinaris ; Lentil ; Restriction site analysis ; cpDNA ; Cytoplasmic bottleneck
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A restriction-site analysis of chloroplast DNA (cpDNA) variation in Lens was conducted to: (1) assess the levels of variation in Lens culinaris ssp. culinaris (the domesticated lentil), (2) identify the wild progenitor of the domesticated lentil, and (3) construct a cpDNA phylogeny of the genus. We analyzed 399 restriction sites in 114 cultivated accessions and 11 wild accessions. All but three accessions of the cultivar had identical cpDNAs. Two accessions exhibited a single shared restriction-site loss, and a small insertion was observed in the cpDNA of a third accession. We detected 19 restriction-site mutations and two length mutations among accessions of the wild taxa. Three of the four accessions of L. culinaris ssp. orientalis were identical to the cultivars at every restriction site, clearly identifying ssp. orientalis as the progenitor of the cultivated lentil. Because of its limited cpDNA diversity, we conclude that either the cultivated lentil has passed through a genetic bottleneck during domestication and lost most of its cytoplasmic variability or else was domesticated from an ancestor that was naturally depauperate in cpDNA restriction-site variation. However, because we had access to only a small number of populations of the wild taxa, the levels of variation present in ssp. orientalis can only be estimated, and the extent of such a domestication bottleneck, if applicable, cannot be evaluated. The cpDNA-based phylogeny portrays Lens as quite distinct from its putative closest relative, Vicia montbretii. L. culinaris ssp. odemensis is the sister of L. nigricans; L. culinaris is therefore paraphyletic given the current taxonomic placement of ssp. odemensis. Lens nigricans ssp. nigricans is by far the most divergent taxon of the genus, exhibiting ten autapomorphic restriction-site mutations.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 181 (1992), S. 11-20 
    ISSN: 1615-6110
    Keywords: Ferns ; Dryopteridaceae ; Polystichum ; rDNA ; restriction site analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Restriction site variation in the nuclear 18S–25S ribosomal RNA genes (rDNA) was analyzed hierarchically in a species complex in the fern genusPolystichum. Two distinct rDNA repeat types were present in all individuals ofPolystichum examined. No variation was detected among individuals within a population ofP. munitum, among populations ofP. munitum orP. imbricans, or among the six diploid species ofPolystichum from North America, including the circumborealP. lonchitis. The identity of rDNA repeats across all six North American species ofPolystichum may reflect an overall similarity of the nuclear genomes of these species, an observation supported by isozyme data as well. However, this nuclear similarity contrasts sharply with the highly divergent chloroplast genomes of these six species. The conservative nature of the rDNA inPolystichum also is in contrast to the much more variable rDNAs of most angiosperms investigated. Perhaps the tempo and mode of evolution of rDNA in ferns differ from those of angiosperms; however, the data base for fern rDNA is very small. Furthermore, the number of repeat types per individual is consistent with a diploid, rather than polyploid, condition despite the high chromosome number (n = 41) of these plants, although homogenization of multiple, divergent rRNA genes cannot be disproven.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 181 (1992), S. 203-216 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Saxifragaceae ; Tiarella trifoliata ; Intraspecific cpDNA variation ; biogeography ; phylogeography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tiarella trifoliata comprises varietieslaciniata, trifoliata, andunifoliata, and is distributed from southeastern Alaska to northern California. We analyzed restriction site variation of chloroplast DNA (cpDNA) using 23 endonucleases in 76 populations representing the entire geographic range of the species and the three recognized varieties. We also employed comparative restriction site mapping of PCR-amplified chloroplast DNA fragments using 16 restriction endonucleases. This species exhibits low cpDNA restriction site variation. No differentiation is evident among varieties of this species based on cpDNA data; some plants of each variety were characterized by each of the two major cpDNA types detected. The two major cpDNA clades, which differ by only a single restriction site mutation, are geographically structured. A northern clade comprises populations from Alaska to central Oregon; most populations analyzed from southern Oregon and California form a southern clade. Populations that possess the typical northern cpDNA type also occur disjunctly to the south at high elevations in the Siskiyou—Klamath Mountain area of southern Oregon and northern California. Conversely, the southern cpDNA type is found disjunctly to the north in the Olympic Peninsula of Washington. Both geographic areas characterized by disjunct cytoplasms are considered glacial refugia.Tiarella trifoliata joins two other species,Tolmiea menziesii andTellima grandiflora, in having well-demarcated northern and southern cpDNA lineages. All three species have similar life-history traits and geographic distributions. We suggest that glaciation may have played a major role in the formation of the cpDNA discontinuities present in these three taxa. The pronounced relationship between cpDNA variation and geographic distribution suggests the potential applicability of “intraspecific phylogeography” to plants via the analysis of intraspecific cpDNA variation. These three examples also join a rapidly growing data base which indicates that cytoplasms are often geographically structured within species and species complexes.
    Type of Medium: Electronic Resource
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