石貂的染色体研究

本文对分布在我国的石貂北方亚种染色体进行了较详细的研究。结果表明２ｎ＝３８,核型为１４（Ｍ）＋４（ＳＭ）＋１８（ＳＴ）,ＸＹ（Ｍ,Ａ）。Ｃ－带显示该亚种的一些染色体着丝粒区域结构异染色质弱化或消失。Ｎｏ,９染色体的短臂完全异染色质化;Ｘ染色体长臂丰出现插入杂色质带;Ｙ为完全结构异染色质组成。     

Partial tetrasomy 9(9pter to 9q2101) due to an extra iso-dicentric chromosome.

A 3-year-old boy with partial No. 9 tetrasomy is described. The patient showed markedly retarded physical and mental development as well as multiple congenital anomalies. Routine chromosome analysis revealed an extra C-group chromosome. It had a pronounced secondary constriction at the proximal part of its long arm. Based on studies by a variety of banding techniques, the extra chromosome was identified to be an iso-dicentric No. 9 chromosome with inactivation of one of the two centromeres, the karyotype being 47,XY, + DIC (9)(Q2101). The value of BrdUrd treatment was emphasized in the detection of a very small piece of euchromatin within a long stretch of constitutive heterochromatin.     

Partial inversion of the secondary constriction of chromosome 9. Does it exist?

Summary Pericentric inversion of chromosome 9, a common abnormality, has been much studied because of its possible genetic effect. Apart from total inversion, in which the whole heterochromatic segment of chromosome 9 appears to be situated on the short arm, some authors describe partial inversion, in which the heterochromatin is found partly on the long arm and partly on the short arm.Our study indicates that firstly, the heterochromatic segment of chromosome 9 is composed of two biochemically different subunits: the heterochromatin of the centromere itself and the heterochromatin of the secondary constriction. Secondly, it suggests that partial inversion of the secondary constriction of chromosome 9 is an unusual event, as the majority of published cases can be interpreted as the result of an increase in the centromeric heterochromatin without alteration of the secondary constriction.Supported by grants from INSERM (A.T.P. 79-110)     

Zur Genetik und Klinik kleiner Chromosomenaberrationen

Summary A family is described wherein a G-chromosome carrying a structural anomaly within the short arm region, is transferred from each of both parents. In the mother, this chromosome has a secondary constriction on the enlarged short arm and in addition normal satellites (Gp+h); this maker chromosome is also found in the maternal grandfather. In the father, the aberrant G-chromosome presents giant satellites (Gs+). At least one of both marker chromosomes is transferred to all four children. Three of these are healthy, the fourth is retarded mentally and statically, and has a number of congenital anomalies. It is discussed whether these small chromosome aberrations range under normal variability or may be responsible for the developmental disorders exhibited in the proband.

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Wesentliche Teile der vorliegenden Arbeit wurden von H. Lohmann als Dissertation der Medizinischen Fakultät der Universität Freiburg i. Br. vorgelegt.     

Preferential breakage of sensitive regions of human chromosomes

Summary Whilst studying the chromosomes of the peripheral blood lymphocytes of normal controls and patients with lymphoproliferative disorders, two examples of preferential breakage of a sensitive chromosomal region were found. A patient with lymphocytic lymphoma had a sensitive region in a C9 chromosome coinciding with the secondary constriction. A healthy woman had one A2 chromosome showing an unusually located secondary constriction in which breakage sometimes occurred.     

Free trisomy 9P in elderly woman.

The karyotype 47,XX,+9p was observed in a 50-year-old mentally retarded woman with dysmorphic facies, severe cerebral malformations, limb deformities, retarded sexual maturation and deviating dermatoglyphs. Banding analysis showed the extra chromosome to be composed of 9p and the proximal part of 9q comprising a large secondary constriction. The breakage point is estimated as 9q13. Hemozygous large C bands were observed in both chromosomes No. 9 as well as in the extra chromosome. Clinically this case can be regarded as a pure 9p trisomy. The mechanism causing the syndrome is thought to be malsegregation of a deleted chromosome No. 9.     

A test of homology between the B chromosome of maize and abnormal chromosome 10, involving the control of nondisjunction in B's

Summary Nondisjunction of B and B-translocation chromosomes occurs regularly in maize at the second pollen mitosis (Roman, 1947; Blackwood, 1956). The mechanism of nondisjunction was studied using the A-B interchange, TB-9b. The B⁹ chromosome of the interchange undergoes nondisjunction at the second pollen mitosis, while the 9^B chromosome does not (Roman, 1947). It was shown that the 9^B chromosome must be present in a plant for nondisjunction of the B⁹ to occur. This is consistent with the reports of Roman on TB-4a (1949) and Longley on TB-10a (1956). It was also demonstrated that the influence of the 9^B chromosome is limited to pollen grains containing it, and does not extend to all the pollen of a plant.A test of homology between the B chromosome and abnormal chromosome 10 was also made. The ability of abnormal 10 to substitute for the 9^B chromosome and induce nondisjunction of the B⁹ was tested. Nondisjunction did not occur at a detectable rate in the presence of abnormal 10, and the results failed to support Ting's proposal (1958) concerning the origin of abnormal 10.     

Meiosis in a male with Down's syndrome

Summary The chromosomes in mitotic and meiotic phases were investigated in a male Down's syndrome case, aged 45. Information was obtained that based on blood and tunica vaginalis cultures, the somatic chromosome complement was found to possess 47 chromosomes with the standard 21-trisomy, and further that the majority of cells from biopsied testicular specimens examined showed the chromosome number 47 in spermatogonia, and 22 autosomal elements consisting of 21 bivalents and a trivalent, together with an X-Y bivalent in the first spermatocytes. The seminiferous tubules contained no mature spermatozoa.Contribution No. 688 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo. This paper is dedicated to Professor Sajiro Makino, Zoological Institute, Hokkaido University, Sapporo, in honor of his sixtieth birthday, June 21, 1966.     

Fine cytogenetical analysis of the band 10A1-2 and the adjoining regions in the Drosophila melanogaster X chromosome

The X chromosome region 9F12-10A7 (7 bands removed by Df(1)v ^l3) was saturated with lethal, semi-lethal, visible and male sterile mutations. A total of 11 complementation groups were found. In the more narrow interval of Df(1)v ^l1 which removes 3 bands (10A1-2, 10A3, 10A4-5) 6 loci were localised. — The band 10A1-2 consists of a sereis of 5 different subunits: (i) silent DNA where no functions were found — at the distal edge of the band; (ii) and (iii) two genes: v and 1(1)BP4; (iv) silent DNA in middle of the band, (v) locus sev on the proximal edge of the band. About 70% of the band's DNA was found to be silent. — Using the set of chromosome rearrangements removing different parts of the band it was shown that these five sequences may function independently from each other.     

Chromosome number and ploidy-level in a Dutch population ofCrenobia alpina Dana (Planaria)

A Dutch population ofCrenobia alpina was found to have a chromosome number of 2n=42. One pair of large chromosomes is acrocentric and probably shows a secondary constriction; one small pair is acrocentric as well. All other chromosomes are metacentric or sub-metacentric; it has not been possible to discriminate with certainty between them. According to the hypothesis ofDahm (1958) populations with, 2n=42 are autohexaploid, the basic genome consisting of seven chromosomes. On basis of the karyotype it was concluded that the Dutch population described here, is not autohexaploid but functionally diploid, perhaps allohexaploid.     

Variation of the chromosome phenotype in zea,solanum and salvia

Summary InSolanum lycopersicum pachytene chromosomes the gradient in chromomere size, originating on both sides of the kinetochore, reveals the following characteristics: 1. a relatively abrupt decrease in size of the large chromomeres, 2. the gradient is related to arm length in 9 of the 12 chromosomes, 3. the gradient is particularly irregular in the short arm of the nucleolar chromosome and in the long arm is not conspicuous, 4. chromosome 6 shows an abrupt interruption in the gradient close to the kinetochore. Salvia viridis andZea mays chromosomes represent intermediate conditions between species with well defined and species without gradients. InSalvia the intermediate condition is manifested by the presence of a very large chromomere on each side of the kinetochore followed by very small chromomeres. In two chromosomes the intermediate condition is particularly apparent. In these chromosomes two chromomeres of intermediate size are present in the proximal region of the long arm. The nucleolar organizing arm has also an irregular pattern in this species.Maize has a less distinct gradient than tomato in all its chromosomes. Chromosomes 3, 4, 5 and 8 are those where the gradient is the least sharp. The nucleolar organizing arm of chromosome 6 has also an irregular pattern.In a translocation between chromosomes 5 and 6 of maize, a segment composed of very small chromomeres from the distal region of 5 which was moved to the right of the kinetochore of chromosome 6, did not change appreciably its phenotype after ten years of cultivation. During the period of cultivation a selection was made for plants where the original phenotype was preserved so that this result cannot be considered as demonstrating an absence of change in chromomere phenotype with changed position.InDrosophila andChironomus salivary gland chromosomes where chromomeres are large, and no selection has been carried out with such a purpose, the pattern and nucleic acid content of the bands is known to change when rearrangements occur within the chromosome.Supported by a grant from the Swedish Natural Science Research Council toA. Lima-De-Faria. This work was partly carried out at the Department of Botany, University of Illinois, U.S.A. during a visit to this department byA. Lima-De-Faria.P. Sarvella's collaboration in this work was done during her stay at the University of Lund.     

Chromosomal polymorphism in Rattus rattus (L.) collected in Kusudomari and Misima

Summary Chromosomes of Rattus rattus (L.), collected in Kusudomari (Nagasaki) and Misima (Sizuoka) were examined. The karyotype revealed a remarkable heteromorphism in chromosome no. 1. The homozygotic, i.e. standard type, was characterized by 13 pairs of telocentric and 7 pairs of metacentric chromosomes. Chromosome pair no. 1 was telocentric. X and Y chromosomes were also telocentrics. 18.4 per cent of rats from Kusudomari and 40 per cent from Misima showed heteromorphic pair in chromosome no. 1. One chromosome of the heteromorphic pair is conspicuous by the subtelocentric centromere. Total length of the telocentric chromosome of no. 1 is almost the same as of its subtelocentric partner. These facts indicate that the subtelocentric no. 1 chromosome might have arisen by a centromeric inversion of the telocentric chromosome. Individuals homozygous for the subtelocentric no. 1 chromosome could not be found in either population. The difference in the frequency of the dimorphics collected in Kusudomari and Misima was statistically significant. Possible causes of the difference are discussed.Dedicated to Professor H. Bauer on the occasion of his sixtieth birthday. — Contributions from the National Institute of Genetics, Misima, Japan, No. 533     

Cytophotometric studies on the DNA content in diploid and polyploid enchytraeidae (Oligochaeta)

The amount of DNA in nerve nuclei was determined by Feulgen cytophotometry in 45 species and cytotypes. The DNA value of spermatids, spermatogonial nuclei and nerve nuclei in newly hatched worms was determined in some species. The total variation in DNA content ranges from a relative value of 0.40 to 4.85. The DNA content in diploid species ranges from 0.40 to 1.12. In two genera (Lumbricillus and Enchytraeus) wide diversification in chromosome numbers at the diploid level is accompanied by wide variation in DNA values, whereas other genera and species groups (Mesenchytraeus, Henlea and Marionina), which are conservative in this respect, are closer in DNA values. In the genus Fridericia constancy in chromosome number is associated with wide variation in DNA values, this may be due to an increase in DNA taking place in old individuals. In 9 out of 10 cases nearly identical ratios are found between chromosome numbers and DNA values in polyploids and related diploids or lower polyploids. Differential polyteny is recorded in two cases.Dedicated to Professor Dr. J. Seiler on the occasion of his eightieth birthday.     

Three cases of minor chromosomal aberrations discovered by prenatal chromosome determination

Summary A case of pronounced secondary constriction of a chromosome belonging to pair No. 9, a case of deletion of the short arms of one of the chromosomes in pair No. 13, and a case of partial trisomy of the distal portion of a chromosome in pair No. 14 were discovered by prenatal chromosome determination. Analysis of the parents' karyotypes enabled the clinical importance of the three different chromosomal aberrations to be elucidated.     

The ultrastructure of the nuclei and the behaviour of the sex chromosomes of human spermatogonia

Summary The nuclear structure of human spermatogonia has been studied with electron microscopical and histochemical methods. Type B spermatogonia have chromatin clumps without any special ultrastructure and several nucleoli. Five different types of nuclear bodies, and besides, a nuclear vacuole, have been observed in type A spermatogonia. Type I bodies are typical nucleoli consisting of three regions: amorphous, fibrillar and granular. Type II, III and V are considered to be atypical nucleoli. Type IV bodies are small chromatin condensations. Type I bodies are the only ones in which RNA was demonstrated by light histochemical techniques and no PAS positive material was found inside the nuclei. The absence of any special ultrastructure in the chromatin from spermatogonia, and the small mass of the chromatin condensations, show that the human X chromosome and perhaps the Y chromosome are not heteropycnotic in the interphasic nuclei of human spermatogonia.Abbreviations Used RNA ribonucleic acid - gonia spermatogonia This work has been supported by a grant (No. 2623) of the Consejo Nacional de Investigaciones Cientificas y Tecnicas, and partially by a grant (C.M. 6522) from the Population Council.We wish to thank Professor R. E. Mancini for his suggestions during this investigation and his support for its achievement, and to Dr. J. C. Lavieri for providing the biopsies.     

赤链华游蛇的染色体组型与银带带型研究

该文研究赤链华游蛇的染色体组型与NOR     

Aconitase (E.C. 4.2.1.3) mitochondrial locus mapped to human chromosome 22: Studies with Chinese hamster-human somatic cell hybrids

Three separate somatic cell fusions were made between Chinese hamster lines and human lymphocytes containing (1) a 3/4 translocation, (2) an X/9 translocation, and (3) a 17/9 translocation. Eleven independently derived hybrids showed that only human chromosome 22 was consistently present when human ACON _m was expressed and absent when human ACON _m was not expressed. These studies assign a gene for human ACON _m to chromosome 22, and are consistent with prior gene-mapping results.This study was supported in part by Grants HD-04612 and HD-05615 from the National Institute of Child Health and Human Development.     

Transmission of a fully functional human neocentromere through three generations

An unusual Y chromosome with a primary constriction inside the long-arm heterochromatin was found in the amniocytes of a 38-year-old woman. The same Y chromosome was found in her husband and brother-in-law, thus proving that it was already present in the father. FISH with alphoid DNA showed hybridization signals at the usual position of the Y centromere but not at the primary constriction. Centromere proteins (CENP)-A, CENP-C, and CENP-E could not be detected at the site of the canonic centromere but were present at the new constriction, whereas CENP-B was not detected on this Y chromosome. Experiments with 82 Y-specific loci distributed throughout the chromosome confirmed that no gross deletion or rearrangement had taken place, and that the Y chromosome belonged to a haplogroup whose members have a mean alphoid array of 770 kb (range 430-1,600 kb), whereas that of this case was approximately 250 kb. Thus, this Y chromosome appeared to be deleted for part of the alphoid DNA. It seems likely that this deletion was responsible for the silencing of the normal centromere and that the activation of the neocentromere prevented the loss of this chromosome. Alternatively, neocentromere activation could have occurred first and stimulated inactivation of the normal centromere by partial deletion. Whatever the mechanism, the presence of this chromosome in three generations demonstrates that it functions sufficiently well in mitosis for male sex determination and fertility and that neocentromeres can be transmitted normally at meiosis.     

The meiotic chromosomes of man

Summary Information was obtained on the chromosome number, and the behavior of autosomes as well as of the sex chromosomes in meiosis in human male germ cells derived from 25 Japanese patients, 4 to 79 years in age, who were hospitalized mostly due to epididymitis, prostate cancer, undescended testes or infertility.In 16 out of the 25 specimens, the chromosome numbers, 46 in 2n and 23 in n, were consistently established together with an XY sex-determining mechanism based on spermatogonial and spermatocyte divisions. No reliable counts were obtained from the remaining 9 cases, because of that they provided no cells for precise investigation.The X and Y chromosomes during the leptotene stage were observed as two separate heteropycnotic bodies lying along the inner wall of the nucleus, while at pachytene they formed a sex-vesicle after homologous pairing. At the diplotene, diakinesis and first metaphase the X and the Y appeared as an isopycnotic bivalent showing an end-to-end association, though there were some cells in which they remained as two separate entities free from contact. Evidence was presented that the X and the Y seemed to associate with each other at the distal end of the short arm of each element.One or sometimes two smallest autosomal bivalents tended to show rather precociously a chiasma-terminalization at the first metaphase.The metaphase chromosomes of the second spermatocytes were evident by the haploid number as well as by their widely diverged chromatids with a characteristic spiral configuration.The testicular materials under study contained in most cases polyploid cells with a considerable frequency in spermatogonia as well as in first and second spermatocytes. Giant sperm heads were observed not infrequently, mostly being abnormal in shape. No significant correlation was obtained between the frequency of polyploid cells and the age of patients so far studied.Contribution No. 679 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo. — It is our pleasure to dedicate this paper to Professor Dr. Hans Bauer, Max-Planck-Institut für Meeresbiologie, Tübingen, in honor of his sixtieth birthday.     

Karyotype Analysis of Speirantha gardenii (Hook.) Baill.

This paper reports the chromosome numbers and karyotype analysis of Speirantha gardenii, which is endemic to China. The material was collected from Huang Shan, Anhui. It is a diploid species. Its somatic chromosome is 2n=38=22m+6sm+10st. The 9th pair is submedian centromere chromosomes, but it has two constrictions. The secondary constriction is on the short arm near centromere. Of the 19 chromosome pairs,secondary constriction is present only in this pair.