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  • 1
    Electronic Resource
    Electronic Resource
    Chromosomal Rearrangements and Speciation in Animals (1969)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Genetics 3 (1969), S. 75-98 
    Details
    ISSN: 0066-4197
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ge.03.120169.000451
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  • 2
    Electronic Resource
    Electronic Resource
    Mehrschwänzige Spermien nach Röntgenbestrahlung von Locusta migratoria (1934)
    Springer
    Naturwissenschaften 22 (1934), S. 59-60 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01498751
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  • 3
    Electronic Resource
    Electronic Resource
    Eine Neue Form von Tetraploidie nach Röntgenbestrahlung (1935)
    Springer
    Naturwissenschaften 23 (1935), S. 390-391 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01498072
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  • 4
    Electronic Resource
    Electronic Resource
    Amount of Heterochromatin as a Specific Character (1943)
    [s.l.] : Nature Publishing Group
    Nature 152 (1943), S. 536-537 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] ONE general fact which emerges from, recent work in animal cytology is that the extent of the hetero-chromatic (‘inert’) segments of the chromosomes often varies very greatly from one species to another, even within the same genus. Thus, among the grasshoppers, Stauroderus scalaris possesses ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/152536b0
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  • 5
    Electronic Resource
    Electronic Resource
    Chromosome Cycle of Ascaris megalocephala (1936)
    [s.l.] : Nature Publishing Group
    Nature 137 (1936), S. 783-783 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] PAINTER1 and Schrader2 have recently suggested that the long chromosomes of the germ-line cells in Ascaris megalocephala are peculiar in having a large number of spindle attachments instead of only one as hitherto assumed. Some time ago, I carried out an experiment ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/137783a0
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  • 6
    Electronic Resource
    Electronic Resource
    Evidence for Polyploidy in the Hermaphrodite Groups of Animals (1940)
    [s.l.] : Nature Publishing Group
    Nature 146 (1940), S. 132-133 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] IT is now well known that a large number of species of higher plants are polyploids, and it is reasonable to infer that polyploidy has been one of the main evolutionary methods of species formation in the angiosperms. In animals a few instances of polyploidy are known in parthenogenetic forms ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/146132a0
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  • 7
    Electronic Resource
    Electronic Resource
    Cytogenetics of the parthenogenetic grasshopper Warramaba virgo and its bisexual relatives (1981)
    Springer
    Chromosoma 82 (1981), S. 453-469 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Cloned highly repeated DNA sequences were used to investigate the origins of W. virgo. The chromosomal and genomic organization of these sequences in the parthenogenetic grasshopper W. virgo and its sexual relatives indicate that W. virgo has had two independent origins. Data from the cloned sequences together with that from rapidly renaturing DNA are consistent with a hybridization event between two sexual species for each origin of the parthenogenetic species. Previously published data on C-banding and other karyotypic features (White and Contreras 1981) strengthen the dual origin conclusion. — The cloned DNA sequences, pWv 1 and pWv 5, have differentiated northern and southern races in the sexual species P196. The southern race appears to have hybridized with another sexual species, P169, to give rise to the Boulder/Zanthus clones of W. virgo. The northern race of P196 may have crossed with a species similar to P169 to give rise to the remaining W. virgo clones which are now present in both eastern and western Australia. White (1980) proposed that the origin of W. virgo was in western Australia and that the eastern populations were established by migration. Consistent with this hypothesis is our finding that the cloned DNA sequences have identical genomic and chromosomal organisation in populations of W. virgo in the two disjunct areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295006
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  • 8
    Electronic Resource
    Electronic Resource
    Chiasmatic and achiasmatic meiosis in African Eumastacid grasshoppers (1965)
    Springer
    Chromosoma 16 (1965), S. 271-307 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Male meiosis follows an entirely normal course in six species of the grasshopper genus Amatonga (Eumastacidae, Euschmidtiinae). 2. In twenty-four species of the Eumastacid subfamily Thericleinae the usual diplotene and diakinesis stages are omitted completely in the male sex, the transition from pachytene to prermetaphase being direct and apparently very rapid. 3. In some of these species chiasmata become visible at the beginning of first metaphase, when the spindle is established. In others the early metaphase bivalents are worm-like structures in which no chiasmata can be seen until mid-metaphase, when the chiasmata are suddenly revealed as loops open out between them. We call the latter type of meiosis cryptochiasmate. 4. In three species of the genus Thericles chiasmata are never seen in the male, even in late metaphase, and observations on first anaphase make it quite improbable that crossing-over has occurred. However, only observation of structurally heterozygous bivalents (which do not occur naturally in these species) will decide this question for certain. 5. In the species which most clearly lacks chiasmata in the male the chromosomes in the oocyte show clear chiasmata (oogenesis has not been studied in the other species).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325995
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  • 9
    Electronic Resource
    Electronic Resource
    Sex chromosomes and meiotic mechanisms in some African and Australian Mantids (1965)
    Springer
    Chromosoma 16 (1965), S. 521-547 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Species of the genus Compsothespis have an X1X2Y trivalent in the male with both ends of the X2 chromosome associated with the same end of the Y. This X1X2Y mechanism must have had an independent origin from the one found in the Mantinae sensu stricto. 2. A second species of Rhodomantis has been shown to have an X1X2Y trivalent in which X1 and X2 are associated with the same limb of the Y, leaving the other limb free. The sex chromosome mechanisms of Compsothespis and Rhodomantis both imply the existence of triple synaptic segments. 3. The genera Bolbe, Ligaria, Hoplocorypha, Antistia, Dystacta, Bisanthe and Harpagomantis have XO males. 4. A species of Dystacta is polymorphic for a pericentric inversion. A species of Hoplocorypha and one of Antista are polymorphic for fusions or dissociations. 5. The genera Sphodropoda, Polyspilota and Archimantis belong to the group of X1X2Y Mantinae sensu stricto. It has been shown that those members of this group which have very small Y-chromosomes have the pairing limbs of the X1 and X2 chromosomes unusually long; it is probable that this situation is due to translocations having occurred whereby material was transferred from the Y to the X's. 6. Bolbe and Harpagomantis are added to the list of mantid genera with achiasmatic meiosis (Callimantis-type) in the male. Achiasmatic meiosis has probably been evolved at least five times in the phylogeny of the mantids. 7. Some comparisons are made between the achiasmatic mechanisms which have evolved in certain mantid genera and in a few species of Thericleine Eumastacid grasshoppers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00326972
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  • 10
    Electronic Resource
    Electronic Resource
    Asymmetry of heteropycnosis in tetraploid cells of a grasshopper (1970)
    Springer
    Chromosoma 30 (1970), S. 51-61 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In XO male grasshoppers (Acridoidea and Eumastacoidea) X-chromatin is negatively heteropycnotic in spermatogonial mitoses. In neo-XY species which have a fusion between the original X and an autosome it is usual for the former alone to show negative heteropycnosis. This is the case in the Australian Morabine grasshopper species “P52a”. In tetraploid spermatogonia of this species, however, which contain two neo-X's and two neo-Y's, only one of the neo-X's has a negatively heteropycnotic left limb, the other X having the same degree of condensation as the autosomes. This novel type of behavior is compared with the heteropycnosis of one of the two X's in the somatic cells of female mammals. It is concluded that the asymmetry of condensation of the two X's in tetraploid spermatogonia of “P52a” demonstrates the existence of a fundamental cellular mechanism which is inherent and only expressed under the abnormal condition of tetraploidy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293909
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