Fundamenta genetica : the revised edition of Mendel's classic paper with a collection of 27 original papers published during the rediscovery era / selection and commentary by Jaroslav Kříženecký ; with introduction by Bohumil Němec.

Date:
1965
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Fundamenta genetica : the revised edition of Mendel's classic paper with a collection of 27 original papers published during the rediscovery era / selection and commentary by Jaroslav Kříženecký ; with introduction by Bohumil Němec. Source: Wellcome Collection.

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    20 J. Lejeune 3 3 a b Fig. 4. A case of insertion. The middle part of short arm of chromosome 3 is inserted in the distal portion of long arm of chromsome 7. (o) Actual karyotype of the in¬ dividual; ib) cut-out of the chromosomes to show arti¬ ficially the inserted piece; (c) the amputated chromosome 3 at left and the long chromosome 7 at right are the original ones (as shown in a). The amputated chromo¬ some 3 at right and the long 7 at left are reconstituted by patching together the cut out fragments seen in (6). The exchanged segments being of equal length, this translocation could not be detected by con¬ ventional staining [17]. The children, carriers of an extra G-like chromosome, are trisomies for the distal portion of the long arm of chromosome 8. This type of reciprocal translocation of equal length had been anticipated long ago [18], but awaited new tech¬ niques for confirmation. There is little doubt that other examples will be discovered, leading eventually to the detection of chromosomal imbalance in abnormal children already classified as normal karyotype with the old techniques. This implies that every negative chromosomal examination of the last 10 years must be reinvestigated with the new techniques, not to mention all the positive findings. Analysis of abnormal cells Although very impressive studies have been de¬ voted to chromosomal changes in neoplastic cells, further cytogenetic analysis was soon blocked because of the impossibility of defining precisely the identity of rearranged chromosomes. Application of the new techniques can radically change this state of affairs and I would like to remark in passing that with Mile Venuat and 3 С Dr Dutrillaux we have been able to observe, in a quasi-diploid malignant strain, a characteristic aberration of chromosome 6, together with a curious streakiness of this element forming pseudo-dicentrics [18]. If the general theory of clonal evolution of the karyotype has any validity, chromatid fine struc¬ ture analysis should soon provide the evidence by demonstrating common variants [19] for some classes of cancer. Eventually this approach could take immediate advantage of the enormous wealth of information already gathered by cell hybridization techniques [20]. The chromosome maps thus established could give a glimpse of the relationships between gene dosage and metabolic pathways as postu¬ lated in the hypothesis of combinaisons inter¬ dites [21]. No doubt the cytogenetics of tumours will change so rapidly in the next few years that any review of this field is actually impossible. Impact on Non-human Cytogenetics Extension of chromatid analysis to animal karyo¬ types was indeed very attractive and many of us have, fortunately, not resisted that temptation. It is well known that the karyotype of the anthro¬ poid apes orang-utan, gorilla, and chimpanzee, had an air de famille and had an obvious resemblance to the human karyotype. A puzzling feature was that although all the elements of the chimpanzee karyotype, for example, shared simi¬ larities with the human (apart from the difference in number—48 in the chimpanzee), there was no Nobel 23 (1973) Chromosome identification