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dc.contributor.authorKoller, P. Ch.en
dc.date.accessioned2019-02-15T14:32:41Z
dc.date.available2019-02-15T14:32:41Z
dc.date.issued1933en
dc.identifier.urihttp://hdl.handle.net/1842/34915
dc.description.abstracten
dc.description.abstract(1) At mitotic prophase unravelling of the chromosome spiral occurs without actual increase in length.en
dc.description.abstract(2) The opening out of the secondary split is at mid -prophase. The actual split most probably does not coincide with the opening out of the sister chromatids during mitosis.en
dc.description.abstract(3) The commencement of mitosis is the fission of genes and this must occur during the resting stage.en
dc.description.abstract(4) The single structure of prophase spiral at mitosis is due to the close association of the homologous genes, chromomeres, and chromatids. The cause of the association is homology, most probably physicochemical in nature.en
dc.description.abstract(5) Unravelling of the chromosome spiral is a condition sine qua non for the building up of the matrix of each chromonema'separately.en
dc.description.abstract(6) Contraction operates from the undivided attachment constriction. This force acts upon the matrix, causing it to decrease gradually in length. The chromonema does not shorten but adjusts itself by forming a spiral. This structure can be recognised in the prophase of the following division (persist - ance of chromosome individuality).en
dc.description.abstract(7) The tertiary split at metaphase was not found in Vicia, Tulipa and Allium. Anaphase separation is due to repulsion which operates between two homologous attachment constrictions.en
dc.description.abstract(8) The loci of pairing at zygotene between homologous chromosomes are at random, but always include groups of chromomeres. Polarisation is caused by special attraction between the ends of chromosomes and centrosomes or nuclear Dole. It is most probably genetical in its oren
dc.description.abstract(9) At pachytene the homologous chromosomes twist around each other.en
dc.description.abstract(10) The opening out of the secondary split is at the end of pachytene.en
dc.description.abstract(11) The general rule of pairing - that association always occurs between pairs of homologues, and repulsion always between pairs of paired homologous constituents, - is demonstrated by several observations.en
dc.description.abstract(12) At the end of pachytene, attraction and contraction produce a torsion. The secondary split introduces the repulsion and as a result of the interaction of these forces, breaks occur. The fusion of partner chromatids produces the chiasma.en
dc.description.abstract(13) Chiasma frequency is not related to the size of the bivalents.en
dc.description.abstract(14) The decrease in the number of chiasmata from diplotene to metaphase is caused by two repulsions . The first is general, operating between pairs of paired chromatids; the second is specific and acts between two corresponding homologous attachment constrictions. If the latter is greater, the result of interaction is movement of the chiasmata, towards the distal end.en
dc.description.abstract(15) The following data supply evidence in favour of Janssens' chiasmatype hypothesis: (a) Pairing of unequal chromosomes; (b) Interlocking of bivalents at meiotic pro - :phase. (ç) Twisting of sister chromatids on both sides of chiasmata; (d) Decrease in genetical crossing -over parallel to a similar decrease in chiasma frequency.en
dc.description.abstract(16) The terminal association of bivalents depends upon a special affinity between terminal chromomeres. If intercalary chromomeres become terminal by trans - location, they attain this special affinity.en
dc.description.abstract(17) The movement of chromosomes towards the equatorial plate is a result of repulsion operating between poles and attachment constrictions only.en
dc.description.abstract(18) Metaphase equilibrium is a result of repulsion between poles and attachments and between attachmen of similar and dissimilar chromosomes.en
dc.description.abstract(19) In some cases the interal affinity of chromosomes will interact with the other forces and determine the mitotic or meiotic metaphase pattern, as it is the case in secondary association and somatic pairing.en
dc.description.abstract(20) The spindle mechanism is necessary for normal chromosome movements before and after metaphase. It guides the chromosomes by their attachment constriction towards equilibrium either at the metaphase plate or at the poles. The spindle can be formed only in a normal cytoplasmic environment.en
dc.description.abstract(21) At anaphase there is a second period of equilibrium where the repulsion between the corresponding attachment constrictions and poles is equal. Further separation is due to the expansion of the inter-chromosomal spindle, for which new evidence is put forward.en
dc.description.abstract(22) At anaphase there is no repulsion between the similar or dissimilar attachments migrating towards the same pole. Repulsion exists only between the corresponding homologous attachment constrictions.en
dc.description.abstract(23) The similarity between effects of forces operating at mitotic and meiotic division and those which act in an electro-magnetic field indicates a close relationship in the nature of those forces.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2019 Block 22en
dc.relation.isreferencedbyen
dc.titleDynamics of chromosome movementen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnameDSc Doctor of Scienceen


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