Showing papers on "Karyotype published in 1972"

Location of ribosomal DNA in the human chromosome complement.

Abstract: Hybridization of 3H-labeled ribosomal RNA to human chromosomes on slides resulted in specific labeling of the satellite regions of chromosomes 13, 14, 15, 21, and 22, with an over-all efficiency of about 5%. Differences between D and G chromosomes, and between associated and unassociated satellites, were not significant. Labeling of all other parts of the preparations was nonspecific, and increased in the order: extrachromosomal regions < chromosome arms < centric regions.

Analytic review: nature and origin of males with XX sex chromosomes.

Abstract: Since the first reports in 1964 of males with the karyotype 46,XX [1-3], over 40 such cases have been reported. A number of problems pertaining to these cases are as yet unresolved. First, there is the question of symptomatology. It is not clear whether 46,XX males form a clinical entity of their own or whether they should be classified merely as variants of Klinefelter's syndrome, as defined clinically. Second, the etiology of the condition has not been clarified. Third, it remains to be considered what pathogenetic mechanisms contribute to the clinical features seen in these individuals. At the present time, a review of the available data may serve to throw some light on these questions. The data presented here will not solve the problems, but it is hoped that by summarizing the present knowledge, it will be easier to define more sharply the tasks of future research in the field. Moreover, a presentation of the solutions that appear to me most likely in the light of present data may provoke discussion which will contribute toward the solution of the questions that are as yet unsettled.

Tetraploid Origin of the Karyotype of Catostomid Fishes

Abstract: Catostomid fishes appear to have 2n(-->4n?) approximately 100 chromosomes. The Cyprinidae, from which catostomids probably diverged before the Eocene, usually have 2n = 48 or 50 chromosomes. Preliminary cytophotometric measurements indicate an approximate doubling of DNA content of cells among catostomids.

Cytological and cytogenetical studies on brain tumors. 4. Identification of the missing G chromosome in human meningiomas as no. 22 by fluorescence technique.

Abstract: Among 70 human meningiomas cytogenetically investigated by us up till now, only 4 tumors showed a hyperdiploidy. 2 of them had a uniform stemline with 47 chromosomes (47,XX,G+ and 47, XY, C(?E)+); the other 2 meningiomas had a stemline with a modal number of 53 (55) chromosomes.

Genetic dissection of neural properties using somatic cell hybrids.

Abstract: A set of neuronal genes can be expressed in neuroblastoma × L cell hybrids and hybrid cell lines with specific defects in neural function can be generated in high yield.

Tumor Etiology and Chromosome Pattern

Abstract: Fibrosarcomas induced in Chinese hamsters and rats by Rous sarcomla virus and 7,12-dimethylbenz(a)anthracene are associated with nonrandom chromosome variation. Although histologically indistinguishable, the tumors induced by the virus or chemical in each host species are characterized by completely different karyotypic patterns.

Robertsonian chromosomal variation and identification of metacentric chromosomes in feral mice.

Abstract: Cytogenetic studies of feral mice (M. musculus) from various but predominantly Alpine areas of Switzerland, carried out on random samples collected by spot-checks, established the widespread existence of metacentric chromosomes in the somatic karyotype. Despite the finding of the common occurrence of some of the metacentrics in different places, the examination of the possible homology or heterology by breeding procedures revealed the surprising fact that independence, partial or heterobrachial homology of the metacentric chromosomes prevail among mice from different geographical areas. Thus, the general picture is that of an array of different metacentric chromosomes derived from independent events of Robertsonian variation in the process of evolution. — While heterozygosity with independent metacentrics within a Robertsonian system may have a bearing on the fertility rate of a given mouse population, a more severe impairment of the reproductive capacity must be taken into account in mouse populations which possess different metacentrics with mono- or heterobrachial homologies. These conditions favour the assumption of the existence of a selective system of reproductive barriers further subdividing the species in many, more or less stable, micro-populations. — The chromosomal arms (telocentrics) involved in the formation of the metacentric chromosomes could be identified by Q- and G-banding techniques in combination with the results of crossbreeding, and were assigned to the corresponding telocentric autosomes of the mouse (Comm. Standard. Genet. Nomenclat. for Mice, 1972). Most of the telocentric autosomes of the mouse are included in one or more of the metacentrics found in the feral populations. By means of their isolation in separate lines, these metacentrics may be useful in experimental biology as marker chromosomes of defined identity carrying known linkage groups.

Assignment of three human genes to chromosomes (LDH-A to 11, TK to 17, and IDH to 20) and evidence for translocation between human and mouse chromosomes in somatic cell hybrids (thymidine kinase-lactate dehydrogenase A-isocitrate dehydrogenase-C-11, E-17, and F-20 chromosomes).

Abstract: Independently derived man-mouse somatic cell hybrids and their derivative subclones show a positive correlation between the expression of human lactate dehydrogenase A subunits and the occurrence of the human C-11 chromosome. Data are also presented that confirm the previously reported linkage of the thymidine kinase locus to the E-17 chromosome. A translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the E-17 chromosome. This translocation also provides evidence for translocation between man and mouse chromosomes in somatic cell hybrids. A presumptive association between the human phenotype for isocitrate dehydrogenase and the human F group is also described. Identification of specific human chromosomes was achieved by the application of several new cytological techniques: measurement of chromosome arm length, in situ annealing with mouse satellite complementary RNA, constitutive heterochromatin staining with Giemsa, and quinacrine mustard fluorochromatic staining.

Reconstruction of the Neurospora crassa pachytene karyotype from serial sections of synaptonemal complexes.

Abstract: Serial sections from isolated asci were used to reconstruct the seven pachytene bivalents of Neurospora crassa. The synaptonemal complex could be traced for its whole length in each bivalent, being attached to the nuclear envelope at both ends in six. The satellite end of the nucleolar chromosome did not appear to be attached to the nuclear envelope. The estimated lengths of the bivalents ranged from 10.7 to 5.1 microns in one nucleus, from 11.5 to 4.2 microns in another, and from 8.5 to 4.4 microns in a third, with total haploid complement lengths of 45.5 microns, 47.3 microns, and 43.9 microns respectively. These values are considerably smaller than published light microscopical measurements.—The synaptonemal complex in N. crassa, as in other ascomycetes, has two banded ca. 400 A wide lateral components held about 1200 A apart by a central region containing the ca. 200 A wide central component. With normal glutaraldehyde/OsO4-phosphate buffered fixation the chromatin of the pachytene bivalents is poorly contrasted. Occasional local thickenings of the central component into electron dense nodes ca. 1000 × 500 A in longitudinal section are characteristic of the complex.

Chromosome studies in a neonatal population

Abstract: The results of chromosome studies on 6809 consecutive newborn infants are presented. One hundred and one (1.48%) were heterozygous for a marker chromosome, the significance of which is not at present clear. Twenty-two infants (0.32%) had a major chromosome abnormality. Only six of these infants (0.09%) had a clinically recognizable abnormal phenotype (Down's syndrome). The occult chromosome abnormalities included five sex chromosome abnormalities (one 47,XYY; two 47,XXY; two 47,XXX) and 11 balanced translocations. Seven of these were t(DqDq) and four were reciprocal translocations. The results of the present survey are combined with four other similar neonatal surveys in which a total of 23,328 newborns have been screened. Of these, 117 (0.5%; range 0.65-0.32%) had major chromosome abnormalities. The majority of these (72.7%) would not have been detected at birth without chromosome studies, an important fact in the context of prenatal diagnosis of chromosome disease and the early ascertainment of high-risk families.

Evolution of karyotypes in snakes.

Abstract: Karyotype analysis and morphometric measurement of the chromosomes of 17 species of snakes have been done. Chromosomes of different species so far worked out in each family have been compared using quantitative methods to derive chromosomal affinities between species of different taxonomic categories. The following conclusions have been drawn: (i) It is suggested that the retention of Xenopeltidae as a separate family is unnecessary and the only species Xenopeltis unicolor referred to in that group should be included in the family Boidae. (ii) The subfamilies, Boinae and Pythoninae cannot be distinguished chromosomally. (iii) On the basis of chromosomal similarities, the cytologically known species of Colubridae. have been put into 13 different groupings which do not always correspond to the views of the present day colubrid taxonomists. (iv) In Hydrophiidae, speciation seems to have occurred through changes in the 4th pair of autosomes and sex chromosomes in general and the W chromosome in particular. Evidences are presented to show that fission and inversion have played an important role in bringing about the structural rearrangements in this group. (v) Family Viperidae according to taxonomists is divided into two subfamilies. Both the subfamilies are chromosomally very similar.

The C-band and G-band patterns of Microtus agrestis chromosomes.

Abstract: The C-band and G-band patterns of Microtus agrestis metaphase chromosomes are described. The C-band pattern reveals constitutive heterochromatin as uniformly intenselystained areas but cannot aid in identifying autosomal pairs. The G-bands revealed by a heat renaturation method (ASG) were compared with those revealed by treatment with three proteolytic enzymes. All procedures yield apparently the same specific pattern of crossbands on the autosomes, and each autosomal pair can therefore be identified by its characteristic pattern. The constitutive heterochromatin of the sex chromosomes stains uniformly with the heat renaturation method but is subdivided into regions with different staining intensities with each enzyme treatment. A G-band karyotype for Microtus agrestis metaphase chromosomes is presented.

A ring-20 chromosome.

Abstract: to be devoid of any genes or factors necessary for normal male development, this raises questions as to why it exists in its present form, and whether it may have some other functions. The existence of the fluorescing portion of the Y long arm may be explained as the result of evolutionary change involving the accumulation of non-functional genes on sheltered chromosomes, which Nei (1970) has demonstrated can occur in a reasonable period of evolutionary time. This process may explain the observed polymorphism in Y length, for unlike the X chromosome, in which deletions or duplications could present problems during meiosis, the Y chromosome has no similar restrictions. Furthermore, since survival is possible without the Y but not without an X chromosome, and since both theX and Y are believed to have evolved from a homologous pair of autosomal chromosomes, there must have been preferential inactivation of the genes of the Y chromosome. This inactivation would promote differentiation between the sex chromosomes and reduce the possibility of crossing-over. Lack of differentiation between the gonosomes could put a species at a selective disadvantage by making for a high incidence of intersex. That such inactivation occurred is suggested by the fact that there is virtually no recombination between the X and Y in organisms with well-differentiated sex chromosomes (Nei, 1970). Despite the lack of structural genes, it is possible that the fluorescing Y long arm does have a function in orienting this chromosome in the sex bivalent during meiosis, when, as has been shown by Pearson and Bobrow (1970), the short arm of the Y enters into a terminal association with the X chromosome. The fact that fertility was not impaired in the present family may indicate that the Y aberration is indeed an isochromosome of the short arm, in which case it would not matter which end associated with the X. On the other hand, diminished fertility was noted by Muldal and Ockey (1962) in a family in which nearly one half of the Y long arm was deleted; and dicentric Ys are associated with infertility, with the X and Y appearing as univalents in the majority of cells at diakinesis (McIlree et al, 1966).

Karyotype analysis of Xenopus muelleri (Peters) and Xenopus laevis(Daudin), Pipidae

Abstract: A cytogenetic analysis of two anuran species, Xenopus laevis laevis and Xenopus muelleri, was performed. The diploid number of chromosomes in both species was 2n

Cytological Mapping of Human X-Linked Genes by Use of Somatic Cell Hybrids Involving an X-Autosome Translocation

Abstract: Man-mouse and man-Syrian hamster somatic hybrid cell lines were prepared by fusion of mouse A9 or hamster TG2 cells, which are deficient in hypoxanthine-guanine phosphoribosyl transferase, with cells of a diploid fibroblastic strain, KOP-1, derived from a woman heterozygous for an X-autosome translocation. 61 clones were derived in nonselective medium and 85 sublines of these were derived in selective media: 53 in hypoxanthine-aminopterine-thymidine and 32 in 8-azaguanine. All three human X-linked markers studied, i.e., hypoxanthineguanine phosphoribosyl transferase (EC 2.4.2.8), glucose-6-phosphate dehydrogenase (EC 1.1.1.49), and phosphoglycerate kinase (EC 2.7.2.3), were present together, or absent together, in most of these clones and sublines. However, loss or retention of only phosphoglycerate kinase was occasionally observed, even in the absence of selective growth, while no evidence of separation of hypoxanthine-guanine phosphoribosyl transferase from glucose-6-phosphate dehydrogenase occurred. Cytological examination of eight man-hamster clonal lines by the quinacrine fluorescent technique showed that human phosphoglycerate kinase was only present when the translocation chromosome carrying most of the long arm of the X chromosome was present. The presence of human glucose-6-phosphate dehydrogenase and hypoxanthine-guanine phosphoribosyl transferase was not related to the presence or absence of this chromosome, but appeared to be correlated with the presence of the other translocation chromosome.

Cat-eye syndrome, a partial trisomy 22.

Abstract: A family is presented in which a phenotypically normal mother and her healthy daughter both had abnormal children with a small supernumerary chromosome. Both had clinical symptoms suggestive of cat-eye syndrome. In both women 1 G-chromosome was found to be replaced by a small submetacentric satellited chromosome. Its fluorescence pattern was compatible with that of a chromosome 22, and so was the fluorescence pattern of the supernumerary chromosome in one of the phenotypically abnormal children. Since complete monosomy G in addition to partial autosomal trisomy would not be compatible with clinical “normality” the respective karyotypes must be interpreted as a small deletion of a chromosome 22 in the healthy mother and daughter and a partial trisomy 22 in their abnormal children. Therefore it can be concluded that a deletion of a chromosome 22 is compatible with a normal phenotype and that the cat-eye syndrome results, at least in this family, from a partial trisomy 22.

Chromosome abnormalities in chicken (Gallus domesticus) embryos: Types, frequencies and phenotypic effects

Abstract: Cytological screening of 4182 chick embryos from 10 strains and 5 strain crosses was performed to determine the types and frequencies of chromosome abnormalities. Gross phenotypic effects, such as growth retardation and malformation, were noted. Clues to the etiology of such chromosome aberrations were also sought. The following euploid series was observed: Haploid mosaics (A-Z/2A-ZZ, A-Z/2A-ZZ/3A-ZZZ, A-Z/A-W/2A-ZW/2A-ZZ, A-Z/A-W/2A-ZW/ 3A-Z?), diploid (2A-ZZ and 2A-ZW), triploid (3A-ZWW, 3A-ZZW, 3A-ZZZ, 3A-ZZZW) and tetraploid (4A-ZZWW and 4A-ZZZZ). Aneuploidy was observed as follows: Trisomy for chromosome numbers 1, 2, 3, 4 and double trisomy 2/5. Trisomy-4 with deletion of 50% of the long arm of one member of the trisomic triplet was observed. A 3A-ZWW embryo was found with two cell populations: one, disomic for chromosome 2 and 6; the other, tetrasomic for 2 and 6. Of the 4182 embryos sampled 1.4% were haploids, 97.5% diploids, 0.8% triploids, 0.1% tetraploids and 0.2% trisomics. On the average 10.8% of the early dead embryos were euploid (excluding diploid) or aneuploid. However, the range for euploidy and aneuploidy among strains was 2.3–23.7% of early deads. Haploid embryos were consistently underdeveloped at 4 days of incubation (D.I.), and died by 5–7 D.I. About 90% of (36) triploid embryos died at or before 4 D.I. The remaining 10% (normal embryos) died prior to hatching. Trisomic embryos were dead or underdeveloped at 4 D.I. Tetraploidy appeared to be lethal at a very early stage. The various strains examined had different overall rates of chromosome aberrations (0.4–8.9%), and also showed different varieties of such aberrations. The modes and possible causes of meiotic, mitotic and fertilization errors are considered. Genetic control of chromosome abnormalities, particularly haploidy, is postulated.

Fission in the evolution of a lizard karyotype.

Abstract: The lizard Anolis monticola has a diploid chromosome number of 48 (24 macrochromosomes and 24 micrcchromosomes). More primitive members of the genus, as determined by bone morphology, have 12 macrochromosomes and 24 microchromosomes. Since the higher chromosome number is the derived condition, this is a case of karyotypic change by centric fission.

Identification of Syrian hamster chromosomes by acetic-saline-Giemsa (ASG) and trypsin techniques.

Abstract: The Syrian hamster karyotype was established by use of known banding techniques with ASG and trypsin. Each pair of chromosomes was definitely identified on the basis of banding patterns. Differences in patterns between the two techniques were limited to resolution of fine bands in some chromosomes. Examination of 4-nitroquinoline-n-oxide transformed cells after use of the trypsin technique made possible accurate identification of numerical changes in chromosome groups and of chromosomes with uncommon banding patterns which occurred subsequent to neoplastic transformation.

A 45,XX,5-,13-,dic+ karyotype in a case of cri-du-chat syndrome.

Abstract: A 45,XX,5–,13–, dic+ karyotype, verified by autoradiography and fluorescence studies, was found in a nine-year-old patient with typical clinical features of the cri-du-chat syndrome. A dicentric trans

Differential Giemsa staining of heterochromatic B-chromosomes in Myrmeleotettix maculatus (Thunb.) (Orthoptera: Acrididae)

Abstract: A modified Giemsa staining technique has been used to investigate the karyotype of the grasshopper Myrmeleotettix maculatus, since this stain appears to be diagnostic for certain repetitive DNAs. The centromeric regions are densely heterochromatic, and further heterochromatic bands occur on the X-chromosome and on both arms of the B-chromosome. The significance of these results is discussed in relation to centromeric structure and B-chromosome structure in this insect, and a possible origin of the B-chromosome is suggested.

Karyotypic variation within the genus Leiopelma (Amphibia: Anura).

Abstract: The chromosome complements of four specimens of the anatomically primitive frog Leiopelma hochstetteri are described from cultured cells and squashes. The basic karyotype in all cases consists of 22 chromosomes, 12 of which are acrocentric. Supernumerary chromosomes are either absent or variable in number, but appear to be constant in the somatic cells of any one individual. The limited evidence available suggests that the supernumerary chromosomes do not pair during male meiosis.The karotype of L. archeyi is described for the first time. Only the smallest pair of the total complement of 18 chromosomes is acrocentric. Supernumeraries are absent.The distribution and probable relationships of the species of Leiopelma are discussed. The karyotypes of Leiopelma and the North American ascaphid frog Ascaphus truei are compared, with particular reference to the relationship of the supernumerary chromosomes of Leiopelma and the microchromosomes of Ascaphus.

Mouse chromosomes identified by trypsin-Giemsa (T-G) banding.

Abstract: Mouse chromosomes have been individually identified through the use of the trypsin-Giemsa (T-G) banding technique. Karyotypes were prepared according to the new standard karyotype of the mouse. Bands obtained with the T-G method correlate with those obtained by other methods, but the T-G technique provides greater detail and demonstrates more bands.

Pericentric enversion of chromosome no. 13 in a large family leading to duplication deficiency causing congenital malformations in three individuals.

Abstract: Received 4 April 1972. * Cytogenetics Laboratory, Genetics Committee of the University of Iceland, Department of Pathology, Reykjavik, Iceland. t Paediatric Department, University Hospital Iceland; Home for the Mentally Retarded, K6pavogur; Paediatric Department, St Joseph's Hospital, Reykiavik, Iceland. t John F. Kennedy Instituttet, GI. Landevej 7-9, Copenhagen, Denmark. ** Faculty of Medicine, University of Calgary, Calgary 42, Alberta, Canada. duplication deficiency derived from a maternal Dgroup pericentric inversion. A female with secondary amenorrhoea, webbed neck, and kyphosis and a chromosome D pericentric inversion was reported by Cohen, Capraro, and Takagi (1966/1967). Crandall and Sparkes (1970) described a pericentric inversion in 9 members of a family, all of whom were phenotypically normal. In the family presented here (Fig. 1) 3 children had congenital malformations. Chromosome analysis could only be performed in 2 of them, both had abnormal karyotypes. Chromosome studies in the family showed that 14 phenotypically normal individuals had an abnormal karyotype which differed from that found in the 2 abnormal children.

Chromosome mapping in the mouse, fluorescence banding techniques permit assignment of most genetic linkage groups.

Abstract: Chromosome banding techniques have permitted the identification of every normal chromosome in the mouse, Mus musculus, and the demonstration of strain differences. By identifying the chromosomes involved in a series of translocations, it has been possible to assign 14 of the 19 known linkage groups to 14 different chromosomes. These powerful cytological methods promise to revolutionize cytogenetic studies in higher organisms.