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  • 1
    Electronic Resource
    Electronic Resource
    On the origin of coding sequences from random open reading frames (1990)
    Springer
    Journal of molecular evolution 30 (1990), S. 104-108 
    Details
    ISSN: 1432-1432
    Keywords: Exon size distribution ; Theoretical function ; Random open reading frame ; Origin of coding sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The size distribution of 411 randomly selected mammalian exons was investigated. This distribution was found to be unimodal with a frequency maximum of 120 bp. Detailed analysis of the distribution demonstrated that larger exons (〉150 bp) have a high goodness of fit to the size distribution of open reading frames (ORFs) in a random sequence, i.e., (61/64)t in which t is the number of triplets. Based on this observation, the general character of the total exon size distribution suggested that this could be defined by a theoretical distribution by superimposing a sigmoid function on the ORF generating function, i.e., (61/64)t×fs(t)×E in which fs(t) is a sigmoid function and E is a constant. We tested this distribution for fitness to the exon distribution using two sigmoid functions. fs(t)=Φ(t) and fs(t)=Bekt/1+Bekt. In both cases a very high goodness of fit was attained. It is concluded that exons have been generated from ORFs in random sequences, that ORFs larger than 150 bp have been selected, irrespective of size, as exons, and that a lower size limit exists below which the probability of an ORF being selected as an exon is very low. These results provide evidence at the molecular level to support the ideas that (1) larger exons have been selected from random ORFs without primary correlation to structural or functional properties at the protein level, (2) there exists a restriction on smaller ORFs to be selected as exons, and (3) the interrupted coding sequences found in eukaryotes represent the ancient form of gene organization that existed prior to the divergence of prokaryotes and eukaryotes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02099936
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  • 2
    Electronic Resource
    Electronic Resource
    Cytoplasmic male sterility inBeta is associated with structural rearrangements of the mitochondrial DNA and is not due to interspecific organelle transfer (1990)
    Springer
    Journal of molecular evolution 31 (1990), S. 365-372 
    Details
    ISSN: 1432-1432
    Keywords: Cytoplasmic male sterility ; Mitochondrial DNA ; Beta ; Sugar beet ; Rearrangement ; Introgression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chloroplast (ct) and mitochondrial (mt) DNAs from four cytoplasmic male sterile (cms) and 22 normal fertile sugar beet lines and accessions of wild beets from the genusBeta have been compared with restriction analyses and Southern hybridizations. We have used restriction analyses of ctDNA as a phylogenetic marker to confirm the taxonomic relationships between the different cytoplasms. According to the ctDNA data, all four cms cytoplasms belong to the same taxonomic section,Beta. Restriction patterns of ct and mtDNA from fertile accessions produced analogous trees of similarity and showed a close correlation between the organellar DNA diversity and the accepted taxonomic classification of the species studied. However, the mtDNA restriction profiles of the four cms types differed dramatically from each other and from those of all fertile accessions from the genus. No indication of cytoplasmic introgression was found in any of the four investigated cms types. Southern hybridization to mtDNA revealed variant genomic arrangements in the different fertile and cms cytoplasms, indicating that rearrangement of the mitochondrial genome is a common denominator to the different cms systems inBeta. It may, indeed, be a common property to spontaneously occurring cms in all or most species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02106051
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Marker-assisted selection of restored male-fertile Brassica napus plants using a set of dominant RAPD markers (1997)
    Springer
    Molecular breeding 3 (1997), S. 449-456 
    Details
    ISSN: 1572-9788
    Keywords: Brassica napus ; bulked segregant analysis ; marker assisted selection ; Ogura restorer ; RAPD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Bulked segregant analysis was used to identify RAPD markers in oilseed rape (Brassica napus L.) that were linked to a male fertility restorer gene for Ogura cytoplasmic male sterility. After screening for polymorphisms using 960 primers, 14 RAPD markers were mapped to a 25 cM region including the restorer locus, a mapping population of 242 F2 individuals being employed. The map was used to select 11 markers that were investigated for polymorphisms between the restorer donor line and 46 recipient lines. A set of four RAPD markers, one in coupling phase with the restorer allele and three with the non-restorer allele, which were informative in all 46 combinations, were used in marker assisted selection of plants homozygous for the restorer allele. A total of 906 homozygous restored plants were found among the 4605 BC1F2 plants analysed. Phenotypic data of a subset of the classified plants was compared with the RAPD data and the expected number of recombinants was calculated from the map data. A close correspondence between the expected and observed numbers of plants with a deviating phenotype was found. Thus, use of a set of dominant RAPD markers provides a way obtaining reliable data for marker-assisted selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009647417936
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    Paper (German National Licenses)
    Fulltext
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