bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonrandom distribution of chromosome breaks in Fanconi’s anemia
Authors: von Koskull Harriet , Aula Pertti
Published: May 2008

Fanconi’s anemia is characterized by an increased amount of chromosome breaks. The distribution of the breaks in the human karyotype was analyzed in chromosome preparations, stained for G-bands, from lymphocyte cultures of five patients with Fanconi’s anemia. The results showed a remarkable nonrandom distribution of breaks. All the breaks were located at the lightly stained chromosome segments. There was a clear clustering of breaks at some chromosome loci, such as 3q27 and 13q32. Relative lengths of the chromosome regions (Paris Conference, 1971) were measured from karyotypically normal cells, and the distribution of breaks in regions was analyzed statistically. The distal regions of the A-group chromosomes, particularly, showed an excess of breaks, whereas the centromeric areas had fewer breaks. The sex chromosomes had a deficit of breaks.
Sister chromatid exchange in human chromosomes from normal individuals and patients with ataxia telangiectasia
Authors: Galloway S.M. , Evans H.J.
Published: May 2008

A new fluorescence plus Giemsa staining technique now makes the detection of sister-chromatid exchange (SCE) a relatively easy matter in cells containing 5-BrdU-substituted DNA. The technique has been applied to human cells to examine the distribution of SCE between different people and between and within different chromosomes. The results show: (1) That there were no large differences in the incidence of SCE between blood leukocyte chromosomes from male and female adults and newborn, and that similar frequencies were found in cells from two patients with ataxia telangiectasia which, nevertheless, showed the typical increases in chromosomal aberrations. (2) The distribution of SCE between chromosomes in the complement was found to be proportional to chromosome length, although the smaller chromosomes were under-represented, but not significantly so. (3) The distribution of SCE within chromosomes was nonrandom, with a deficiency in the centromeric and an excess in the mid-arm regions. There was no evidence for an excess of SCE in chromosome regions rich in AT DNA sequences. (4) The frequency of SCE is to some extent dependent on 5-BrdU concentration, but the influence of concentration is minimal within the range of from 1 to 160 µm. Human cells exposed over two cell cycles at these higher BrdU levels have around 14 SCE per cell–a frequency virtually identical with that observed in cultured cells from the Chinese hamster, wallaby, and rat kangaroo.
Analysis of the karyotype of two species of gibbons (Hylobates lar and H. concolor) by various banding techniques
Authors: Dutrillaux B. , Rethoré M.O. , Aurias A. , Goustard M.
Published: May 2008

The mitotic chromosomes of two species of gibbons (Hylobates lar and H. concolor) are examined and compared, using various banding techniques. These two species have very different karyotypes. At the most, seven pairs of chromosomes have a similar banding pattern. The other elements generally differ by complex structural rearrangements. Thus, it is difficult to propose a scheme for chromosomal evolution at this stage. Comparison with the karyotypes of man and anthropoid apes also shows very important differences; very few chromosomes are common or only slightly modified. Some considerations about the hypothetical origin of particular chromosomal structures are given.
Familial transmission of a (21q22q) translocation
Authors: Buckton K.E. , Newton M.S. , Lauder I.J. , De Mey R. , Elliot D. , Skinner R.
Published: May 2008

A large family is described in which a (21q22q) Robertsonian translocation is segregating through three generations. The assessment of the risk of a translocation carrier producing an offspring with Down’s syndrome is calculated from the data in this family and eight others reported in the literature. The risk when the translocation carrier is a female is approximately 6 in 100, or 0.06. For the male translocation carrier the risk can only be guessed, since the patients with Down’s syndrome born to these parents were probands. The risk for Down’s syndrome from the combined data of male and female translocation carriers is 3 in 100, or 0.03.
Regional mapping of the human No. 1 and X chromosome in interspecific cell hybrids using an X/1 translocation
Authors: De Wit J. , Bootsma D. , Pearson P.L. , Westerveld A.
Published: May 2008

Fibroblasts from a carrier of an X/1 translocation, 46, XY, t(X;l)(q28;q31), were fused with Chinese hamster cells. The resulting hybrids were analyzed for human No. 1 and X-chromosome markers. The data indicate that the loci for PGM1, PGD, PPH, and GuK1 are situated either in the long arm proximal to a break point in band lq31 or in the short arm. The loci for Pep-C, FH, and GuK1 are located distal to the break point. HPRT and G6PD are probably situated distal to a break point in band q28 of the X chromosome; α-Gal A is situated proximal to the break point, either on the long or short arm of the chromosome.
Comparative cytochemical measurements in the diploid-tetraploid species pair of hylid frogs Hyla chrysoscelis and H. versicolor
Authors: Bachmann K. , Bogart J.P.
Published: May 2008

Hyla versicolor (2n = 48) is a tetraploid counterpart to H. chrysoscelis (2n = 24). Cytochemical measurements revealed that no cytological parameter of the two species conformed to the expected 2:1 ratio. Every cytological factor of the tetraploid appeared to have been regulated toward the diploid level. H. versicolor-to-H. chrysoscelis mean ratios and their standard errors were: DNA, 1.90 ± 0.03; nuclear histone, 1.70 ± 0.18; nuclear RNA, 1.63 ± 0.19; total nuclear protein, 1.46 ± 0.05; nuclear sizes, 1.42 ± 0.08.
Chromosome polymorphism in a human newborn population
Authors: Müller Hj. , Klinger H.P. , Glasser M.
Published: May 2008

Replicate chromosome preparations of umbilical-cord-blood leukocytes from 376 neonates born at the Albert Einstein College Hospital, Bronx, New York, were stained with C-, Q-, and G-banding methods to determine the frequencies and distributions of the variable chromosome bands. The C-band variants of primarily chromosomes 1, 9, and 16, as well as those of the remaining C-, E-, and F-group chromosomes, and the brightly fluorescing Q-band variants of chromosomes 3 and 4 and all of the acrocentrics, including the Y, were similarly analyzed. Polymorphism of these chromosome regions was so extensive that the idiogram of each of the 376 newborns of this study had a unique variant pattern, even when only the C- or only the Q-band patterns were compared. The distribution of polymorphic Q-bands in the population sampled was consistent with the expectations of the Hardy-Weinberg law, with the exception of chromosomes 3 and 22, where some deficiency of individuals with “homozygous” Q-band patterns was found. The baseline data presented here reinforce the view that polymorphic chromosome characteristics are very useful markers for characterizing the karyotype of an
A quantitative study of the second meiotic metaphase in male mice (Mus musculus)
Authors: Beatty R.A. , Lim M.-C. , Coulter V.J.
Published: May 2008

Over 11,000 second meiotic metaphase spreads stained for the pericentromeric region have been studied quantitatively in male mice of 14 strains. The sex-chromosome constitution of a cell could be judged objectively if X and Y chromosomes and ploidy were all scored. A bias arose if only Y chromosomes and ploidy were scored but could be corrected statistically. There was no sign of other forms of bias. The original contiguity of X and Y second metaphases in vivo was very occasionally evident in the preparations. Most of the subhaploid aneuploid counts were assumed to be artifactual. The incidence of truly aneuploid second metaphases in 13 strains was estimated as 0.38 ± 0.12 %. The estimated average rate per chromosome was 0.019 ± 0.006 °/°, with a comparable order of magnitude for the sex chromosomes alone. Simultaneous aneuploidy of two or more chromosomes of the haploid set was estimated to be very rare. Of the spreads from 13 strains, 9.6 % were polyploid (2N, 3N, 4N) and showed most of the possible combinations of sex chromosomes. Nearly all the polyploid spreads were considered to arise by artifactual cell fusion at the time of second metaphase during the preparative technique, especially of the X and Y daughter-cell products of the first meiotic division. Other modes of origin (true polyploidy, accidental superposition of cells during preparation) were unlikely. The data could be accommodated by a statistical model with only four parameters. It allowed for artifactual fusion mainly between daughter cells but also between non-daughter cells, bias in one scoring method, and bias in the numbers of cells with given ploidy successfully mounted. Current techniques of chromosome preparation were thought to be wholly unsuitable for the recognition of true polyploidy. The artifactual origin of polyploid spreads was borne out by an absence of polyploid spermatozoa in 14 strains. There appeared to be a virtually constant transmission rate of paternal X and Y chromosomes from early meiosis to late blastocyst. The estimated rate of 49.05 ± 0.67 % with a Y chromosome also estimated the primary sex ratio. There was evidence of polymorphism in autosomal pericentromeric staining in 3 strains. No measure of the numbers of autosomes or sex chromosomes varied significantly between duplicate preparations or between duplicate males of a strain.
Variegated translocation mosaicism in human skin fibroblast cultures
Authors: Hoehn H. , Bryant E.M. , Au K. , Norwood T.H. , Boman H. , Martin G.M.
Published: May 2008

The term “variegated translocation mosaicism” is used to describe the repeated occurrence, within cultures of human skin fibroblasts, of a multiplicity of chromosomal rearrangements. With respect to the frequencies of such cytogenetically aberrant clones we found that they (1) were not detectable in routine diagnostic skin fibroblast cultures from 29 subjects with a wide variety of indications for biopsy; (2) were not detectable during in vitro aging of diploid strains with four normal individuals; (3) could be detected after rescue from bacterial contamination of a culture from an otherwise normal diploid male; (4) occurred with high frequencies in independent cultures from another apparently normal subject; (5) occurred with high frequencies in multiple biopsies obtained at autopsy from a patient with Werner’s syndrome who died of sepsis; (6) were of pseudodiploid nature; and (7) involved a different spectrum of chromosomes in different individuals. A consistent association with mycoplasma contamination could not be made.
Confirmation of the synteny of the human genes for mannose phosphate isomerase and pyruvate kinase and of their assignment to chromosome 15
Authors: Chern C.J. , Croce C.M.
Published: May 2008

The synteny of human mannose phosphate isomerase and pyruvate kinase and the assignment of the genes for these two enzymes to chromosome 15 were confirmed by analysis of 43 independently derived human-mouse hybrid clones. Hybrids between mouse cells deficient in hypoxanthine-guanine phosphoribosyl-transferase and human fibroblasts carrying an X/15 chromosome translocation were also included in this study.
Centromeric and telomeric staining regions in the chromosomes of cattle (Bos taurus)
Authors: Diamond J.R. , Dunn H.O. , Howell W.M.
Published: May 2008

Two new types of staining regions exist after treatment with a modified version of the ammoniacal-silver technique (Howell et al., 1975), in addition to findings by many other researchers working on the chromosomal complement of Bos taurus. Densely stained regions appear to be associated with the centromeres of many of the 29 pairs of acrocentric chromosomes, but there are also 4–6 of the same acrocentric chromosomes bearing telomeric staining regions (TSRs) at the ends of their long arms. In many metaphases examined, actual physical connectives were observed between both types of these ammoniacal-silver staining regions.
Cytogenetic investigations in families with ataxia-telangiectasia
Authors: Cohen M.M. , Shaham M. , Dagan J. , Shmueli E. , Kohn G.
Published: May 2008

Chromosomal studies were performed on peripheral blood lymphocytes and cultured skin fibroblasts from five Israeli-Moroccan families with ataxia-telangiectasia. A total of 24 individuals, including seven propositi, was investigated. Among the probands, significantly elevated rates of chromosome damage were observed in both blood and skin. Skin fibroblasts of affected individuals showed several orders of magnitude more chromosome breakage than lymphocytes. Increased rates of chromosome damage were also observed in the fibroblasts of some phenotypically normal family members (obligate heterozygotes and sibs) when compared to normal controls. An apparent abnormal clone of cells, possessing a large acrocentric marker chromosome (14q+), was observed in varying proportions among cells of all the propositi (2–5 % of lymphocytes; 1–9 % of fibroblasts).
Fluorescent characteristics of drumsticks, drumstick-like projections, and other nuclear bodies in human blood cells
Authors: Mukherjee A.B. , San Sebastian J.
Published: May 2008

The fluorescent properties of drumsticks, drumstick-like appendages, and other nuclear bodies in the polymorphonuclear leukocytes from six human males and females were studied with the aid of the quinacrine-mustard staining technique. Both brightly and weakly fluorescent drumsticks (in females) and drumstick-like bodies (in males) were observed, and they were readily differentiated on the basis of size, shape and, usually, fluorescent intensity. An analysis of the correlation between the extent of nuclear lobulation of the polymorphs and the corresponding fluorescent patterns of the adjoining drumsticks and drumstick-like bodies indicated that a possible change in the state and/or condensation of chromatin in these nuclear bodies might occur with increasing age of the polymorphs. Although the brightly fluorescent regions of the nuclei usually corresponded to the areas darkly stained with Giemsa, much finer patterns of differential staining of drumsticks and other nuclear bodies were obtained only by the fluorescent method.
Comparison of G-, Q-, and R-banding in 28 cases of chromosomal abnormalities
Authors: Verma R.S. , Peakman D.C. , Robinson A. , Lubs H.A.
Published: May 2008

Twenty-eight cases of chromosomal abnormalities were ascertained using G-banding. Seventeen of these had structural abnormalities of a complex nature and are discussed in detail. An independent assessment of chromosome abnormalities was carried out using sequential Q- and R-banding. In no case was there a difference in the identification of the abnormal chromosome, but in two cases a more precise localization or definition of the abnormality was obtained from the R-banded cells. In one case the initial diagnosis of the terminal deletion was altered to interstitial deletion; in the second case a break point in one chromosome involved in a reciprocal translocation was found to be in a different band by R-banding. In several others better delineation of break points or confirmation of complex abnormalities was obtained from the R-banded cells. R-banding was especially helpful in the localization of break points because of the color differentiation obtained with acridine orange. Q-banding was not found to have added any additional information. It was concluded from this study that the use of both G-banding and R-banding in complex abnormalities proved worthwhile.
Location of nucleolar organizing regions on the chromosomes of the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus)
Authors: Bigger T.R.L. , Savage J.R.K.
Published: May 2008

Terminal chromosome associations (“satellite associations”) in ASG-banded preparations have been used to determine the number and location of satellites in the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus). Five pairs of satellites are found in the former and four in the latter. Nucleolar organizing regions (NORs) were visualized with the Ag-AS silver precipitation technique, and their number and position corresponded exactly with the number and position of satellites in Phodopus, where positive chromosome identification can be made in the absence of banding. Numerical agreement is exact in Mesocricetus as well, and the morphology of the silver-tagged NOR-bearing chromosomes strongly suggests that correspondence also occurs in this species.
Chiasmata, meiotic univalents, and age in relation to aneuploid imbalance in mice
Authors: Polani P.E. , Jagiello G.M.
Published: May 2008

Chiasmata were counted and paired and unpaired configurations at first meiotic division and chromosome errors at second meiotic division were assessed at different ages in males and females of two strains of laboratory mice. In the females a decrease of chiasma frequency and an increase of univalents at first meiotic metaphase (MI) were confirmed. In the males, diakineses had higher chiasma frequencies (in the range of the female Mis) and fewer univalents than the MIs had. In these male cells there was no decrease of chiasmata or increase of autosomal univalents with age, and there were some interstrain differences. In the older females there was no parallelism between the frequencies of univalents at MI and the chromosome errors that could be identified at second meiotic division; these were fewer than might be expected on the assumption that all the univalents were true univalents. The relevance of this finding to the question of the nature of most of the univalents observed at first meiotic division in aged female mice is discussed.
Further evidence of X-linkage of hypoxanthine phosphoribosyl-transferase in the mouse
Authors: Hashmi S. , Miller O.J.
Published: May 2008

A variant of the HPRT- A9 mouse cell line was fused with wild type diploid mouse bone marrow cells to obtain an HPRT+ line. The unique chromosomal features of the A9 parent, including the presence of a t(X;3) translocation and the absence of normal chromosomes 15, 16, 17, 18, and the X, have permitted use of this intraspecific hybrid for chromosome mapping. Back-selection of hybrid cells in 8-azaguanine for loss of HPRT resulted in the loss of the X chromosome derived from the diploid parent, providing evidence of the X-linkage of the HPRT locus.
A mitotically unstable human dicentric Y chromosome in a male pseudohermaphrodite
Authors: Buchanan P.D. , Wyandt H.E. , D’Ercole A.J. , Rao K.W. , Hartsell M.L.
Published: May 2008

A patient with a mitotically unstable dic(Y)(pll) chromosome is reported. Physical examination revealed a small penis with severe hypospadia, undescended testes, rudimentary vagina, uterus, left fallopian tube, and no stigmata of Turner syndrome. Longitudinal chromosome studies over a four-year period, including blood, skin, foreskin, and testicular tissue, revealed 45, X/46, X, dic(Y)(pll)/46, X, del(dicY) mosaicism. The proportions of these cells varied in the different tissues, and only 45, X and 46, X, del(dicY) were major cell lines in testicular tissue. Additional minor cell lines were present mainly in peripheral blood: 47, X, dicY, dicY; 47, X, dicY, del (dicY); and 47, X, del(dicY), del(dicY). Premature disjunction of one of the centromeres in a high percentage of the dicentric Y chromosomes in metaphase was observed by Q- and C-banding. Lymphocytes at anaphase and telophase showed lagging Y chromosomes, fragments, and nondisjunction. These observations indicate a high degree of mitotic instability and thus raise the question of the effect of premature centromeric disjunction on mitotic instability of dicentric chromosomes.
Effects of Hoechst 33258 on human leukocytes in vitro
Authors: Pimpinelli S. , Prantera G. , Rocchi A. , Gatti M.
Published: May 2008

The benzimidazole derivative Hoechst 33258 was added at various concentrations to human leukocyte cultures. After 16 or 24 h of treatment, with concentrations equal to or greater than 100 µg/ml of Hoechst 33258, a number of chromosomes showed regions in which the chromatin was undercontracted. The centromeric regions of chromosome 1 and, more rarely, of chromosomes 3 and 9 appeared to be decondensed. Short decondensed regions were also present on the long arms of chromosomes 1 and 2. The possible nature of these regions is discussed.
Human mitochondrial NADP-dependent isocitrate dehydrogenase in man-mouse somatic cell hybrids
Authors: Bruns G.A.P. , Eisenman R.E. , Gerald P.S.
Published: May 2008

Human mitochondrial NADP-dependent isocitrate dehydrogenase (IDH-2) is expressed in man-mouse somatic cell hybrids as a dimeric molecule. The gene specifing this enzyme was observed to be syntenic with the mannose phosphate isomerase locus in the 56 primary man-mouse clones in this series. The human IDH-2 locus, therefore, may be assigned to chromosome 15.
Cytological demonstration of mitotic crossing-over in man
Authors: Therman E. , Meyer Kuhn E.
Published: May 2008

Quadriradial (QR) configurations from four different human lymphocyte meta-phase samples have been analyzed: a patient with Fanconi’s anemia; normal female cells X-irradiated with 150 or 200 R in S or G2; spontaneous QRs occurring in 13,584 metaphases; and cells from two sibs with Bloom’s syndrome. That mitotic chiasmata are caused by crossing-over rather than by random breakage and reunion was concluded from the following observations: (1) In the spontaneous sample, mitotic chiasmata are about as frequent as all other QRs together. (2) The frequencies of mitotic chiasmata and of other QRs are not correlated in the different samples. (3) The break points in other QRs are situated at random relative to chromosome length, whereas the distribution of chiasmata is highly nonrandom. (4) Although the centromeres of chromatid translocations occur in alternate and adjacent positions with approximately equal frequencies, there are very few adjacent counterparts to mitotic chiasmata. These can best be interpreted as a result of an abnormal U-type rejoining of chromatids in a chiasma. (5) Chiasmata found in heteromorphic chromosome pairs show that crossing-over has, indeed, taken place.
Chromosomal evolution in Malagasy lemurs
Authors: Rumpler Y. , Dutrillaux B.
Published: May 2008

The successive use of several banding methods permitted us to compare the karyotypes of six Malagasy lemurs: Microcebus murinus, Lemur fulvus fulvus, L. f. collaris, L. f. albocollaris, L. macaco, and L. mongoz. A correspondence can be found among all clearly identifiable chromosomes. Based on rearrangements of some of the chromosomes, the karyotype of M. murinus seems to be closest to that of the hypothetical common ancestor. The karyotype of L. f. fulvus, which is nearly identical to that of M. murinus, gives rise to those of other forms by several rearrangements.
A polymorphic structural rearrangement in the chromosomes of two populations of orangutan
Authors: Seuánez H. , Fletcher J. , Evans H.J. , Martin D.E.
Published: May 2008

A rearranged chromosome 9 was found in 12 of 23 specimens of orangutan, 4 of Bornean and 8 of Sumatran origin. Nine animals were heterozygous, and 3 were homozygous carriers for the variant chromosome, which was also traced in 4 other animals not studied by us. This type of chromosome rearrangement has been previously described (Seuánez et al., 1976) and is probably the same chromosome shown by Lucas et al. (1973) and reported by Turleau et al. (1975) in other specimens. There is obviously a very high incidence of this variant chromosome 9 in Pongo pygmaeus, and it is unlikely that it could result from independent rearrangements occurring in unrelated specimens from two geographically isolated populations (Sumatran and Bornean). It is concluded that the rearrangement is of ancient origin and that it has been maintained in the populations of Pongo as a balanced polymorphism. This type of complex rearrangement resulting from two pericentric inversions, one inside the other, is compared with certain sporadic pericentric inversions in the human complement, with pericentric inversions which are polymorphic in other mammals, and with pericentric inversions involved in chromosome evolution in the Hominoidea.
Localization of the structural genes for hexokinase-1 and inorganic pyrophosphatase on region (pter→q24) of human chromosome 10
Authors: Chern C.J.
Published: May 2008

Concordant expression of human hexokinase-1 and inorganic pyrophosphatase was established in somatic cell hybrids between thymidine kinase-deficient Chinese hamster cells and human fibroblasts carrying a translocation of the distal third of the long arm of chromosome 10 to chromosome 17. Neither human hexokinase-1 nor human inorganic pyrophosphatase expression segregated concordantly with human cytoplasmic glutamic-oxaloacetic transaminase expression.
The effect of cations on C-band formation in human chromosomes
Authors: Scheres J.M.J.C.
Published: May 2008

A number of salt solutions were tested for their ability to replace 2 × SSC in the production of C-bands with the so-called CT technique. Those containing monovalent cations, except for the ones with Ag+ ions, were capable of inducing C-bands in Ba(OH)2-pretreated human chromosomes. Cesium cations were the most effective in this respect. In contrast to the effect of the monovalent cations studied, di- or polyvalent cations (and Ag+ cations) were incapable of producing C-bands, but appeared to stabilize the Ba(OH)2-induced reverse-banding pattern. This stabilizing effect was obtainable with relatively low cation concentrations and persisted even when C-band-producing cations were present at the same time. The experiments clearly show that the cations present during salt incubations, generally used in the CT- and several other banding methods, can exert a pronounced influence on chromosome behavior.
Stability of centromere-center distances in normal human metaphases
Authors: Kirsch-Volders M. , Hens L. , Susanne C. , Galperin-Lemaitre H.
Published: May 2008

Centromere-center distances were analyzed in 50 normal female and 100 normal male metaphases. Compared with the random distribution of all chromosomes, chromosome pair 6 had a significantly different distribution in both female and male metaphases. Moreover, a significant peripheral location of chromosome pairs 4 and 5 and a significant central location of chromosome pairs 13, 15, 21, and 22 were found in male metaphases. But no specific peripheral location could be assigned to the X or Y chromosomes. No inter- nor intraindividual differences or sex-dependent variation in centromere-center distances were observed. Variance analyses demonstrated consistent centromere-center distances in normal human metaphases obtained from individuals of the same age. The constancy of these chromosome distributions may correlate with chromosome duplication pattern, chromosome length, and chromosome structure.
Nonrandom sex-chromosome association and constitutive heterochromatin in the brush-tailed possum, Trichosurus vulpecula (Marsupialia: Phalangeridae)
Authors: Murray J.D.
Published: May 2008

Nonrandom associations between the short arms of the sex chromosomes of six Trichosurus vulpecula were studied in 455 cells from the spleen and bone marrow. The association occurs in both sexes and was found to be independent of age. There was, however, a significant difference in the degree of association between the two tissues studied. Regions of constitutive heterochromatin were found to be located in the short arms of the X and Y chromosomes by using a C-banding technique. Nucleolar organizers were detected in the middle of the long arm of the X chromosome and in the short arm of the Y chromosome by N-banding. These results indicate that the nonrandom association of the sex chromosomes may reflect an association between heterochromatin regions during interphase of the cell cycle.
Origin of triploidy and tetraploidy in man: 11 cases with chromosome markers
Authors: Kajii T. , Niikawa N.
Published: May 2008

Sixteen triploid and one tetraploid human abortuses were studied for the origin of polyploidy using a sequential Q- and R-banding technique. Ten triploid abortuses provided informative data: one originated in the maternal first meiotic division; five apparently resulted from dispermy; two derived from an error during either the paternal second meiotic division or the first mitotic division; and the last two were of paternal origin. The results indicate that paternal factors, especially dispermy, are the predominant sources of triploidy in man. The tetraploid abortus showed duplication of both the maternal and paternal haploid sets, suggesting normal division of chromosomes and suppression of cytoplasmic cleavage at the first mitotic division. No correlation was found between the origin of polyploidy and the phenotype of the triploid abortuses, nor between the origin of polyploidy and the maternal use of oral contraceptives.
Supernumerary chromosomes in the black rat (Rattus rattus) and their distribution in three geographic variants
Authors: Yosida T.H.
Published: May 2008

Supernumerary chromosomes have been examined in 352 black rats, covering three geographic variants, by use of conventional and C-band staining techniques. Metacentric supernumerary chromosomes, one to three in number, were found in Malayan black rats (Rattus rattus diardíi), with 2n = 42, in Indian black rats (R. rattus rufescens), with 2n = 38, and in Ceylonese black rats (R. rattus diardii), with 2n = 40. The supernumeraries had similar morphology and stained heavily along their entire length by C-band staining. These findings suggested that the supernumeraries had originally developed in the Asian-type black rats and then were sequentially transmitted to the Ceylonese and Oceanian-type black rats, probably in southwestern Asia. A subtelocentric supernumerary chromosome found in one Japanese black rat seemed to have developed independently from the above metacentric supernumeraries.
Specific chromosome changes associated with rabbit cell lines cultured in vitro
Authors: Yang D.P. , Rosanoff E.I.
Published: May 2008

Thirty-three rabbit cell lines were established from various fetal tissues of the inbred strain III of the New Zealand rabbit (Oryctolagus cuniculus). None of these lines exhibited senescence during a growth period of more than 2 years. Karyologic studies of most cell lines at 10 to 20 cell-passage intervals revealed that the karyotype stability of the rabbit cells in vitro was correlated with the organs from which the cell lines were derived. Thus, lines derived from cornea, spleen, and kidney tissues usually contained high frequencies of polyploidy in their early passages, whereas most of those derived from lung and skin were found to retain the normal diploid karyotype for much longer periods of time. One line derived from fetal lung tissue, designated Lung 16, remained diploid up to 100 passages. In late passages of the majority of all the lines studied, the cells became pseudodiploid, hyperdiploid, or polyploid. Among the pseudodiploid and the hyperdiploid cell lines, the chromosomal changes followed three basic patterns: (1) a gain of one or more telocentric chromosomes; (2) a loss of one telocentric chromosome plus a metacentric marker chromosome (M); or (3) a gain of a long telocentric marker chromosome with or without changes in the number of telocentric D chromosomes. By the G-banding technique, the telocentric chromosome involved in these three patterns was identified as the D-group chromosome 18 and the M marker chromosome as an isochromosome of 18. These results suggest that chromosomal rearrangement in rabbit cells involving trisomy of 18 may be responsible for the longevity of these cell lines cultured in vitro.
Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids
Authors: Burgerhout W.G. , Leupe-de Smit S. , Jongsma A.P.M.
Published: May 2008

The position of genes coding for PGD, PPH1, UGPP, GuK1 PGM1, Pep-C, and FH on human chromosome 1 was investigated by analysis of karyotype and enzyme phenotypes in man-Chinese hamster somatic cell hybrids carrying aberrations involving chromosome 1. Suitable hybrid cell lines were obtained by X-irradiation of hybrid cells carrying an intact chromosome 1 and by fusion of human cells from a clonal population carrying a translocation involving chromosome 1 with Chinese hamster cells. The latter human cell population had been isolated following X-irradiation of primary Lesch-Nyhan fibroblasts. In addition, products of de novo chromosome breakage in the investigated hybrid lines were utilized. By integrating the results of these analyses with earlier findings in our laboratory, the following positions of genes are deduced: PGD and PPH1 in 1q36→1q34; PGM1 in 1p32; UGPP in 1q21→1q23; GuK1 in 1q31→1q42; Pep-C in lq42; and FH in 1qter→1q42.
Preleptotene chromosome condensation in mouse oogenesis
Authors: Hartung M. , Stahl A.
Published: May 2008

In the embryonic mouse ovary, studies of meiotic onset reveal the existence of a preleptotene stage of chromosome condensation. This stage begins with the appearance of very fine and irregular filaments, which gather around the chromocenters constituted by centromeric heterochromatin. At maximal condensation the nucleus contains 40 compact chromosomal masses. Decondensation engenders the reappearance of filaments more dense and regular than those seen at the onset of the condensation stage. The filaments elongate while progressively taking on the appearance of leptotene-stage chromosomes. The oocytes at different phases of condensation stage represent 41 % of the germ cells in the 13-day-old mouse embryo. This proportion reaches 63 % at 14 days and then declines to 3 % at 17 days. Spectrophotometric studies of the condensation-stage nucleus, following staining by the Feulgen reaction, indicate that the nucleus contains 4C DNA. This observation, together with the morphologic characteristics of this stage, suggests that the oocyte is already engaged in prophase. Time studies indicate that the condensation stage occurs immediately prior to leptotene.
Assignment of the human gene for enolase 1 to region pter→p36 of chromosome 1
Authors: D’Ancona G.G. , Chern C.J. , Benn P. , Croce C.M.
Published: May 2008

Somatic cell hybrids between mouse cells and human cells carrying a reciprocal translocation between chromosomes 1 and 7 were tested for the expression of human enolase 1 (ENO1) by starch-gel electrophoresis. The results indicated that the gene for human enolase 1 can be assigned to the region p36→pter of human chromosome 1.
Replication pattern of the X chromosomes in three X/autosomal translocations
Authors: Hagemeijer A. , Hoovers J. , Smit E.M.E. , Bootsma D.
Published: May 2008

Three X/autosomal translocations, two familial and one de novo, were analyzed. Late-replicating chromosomes and chromosome regions were studied with R-banding techniques after BrdU incorporation. The first translocation, t(X;4)(q21;ql3), was a de novo translocation, found in a woman with amenorrhea. The structurally normal X was late replicating in all cells. The second translocation, t(X;6)(p21;q26), was found in an unbalanced form, 46, XX, der(6), in a phenotypically abnormal girl; her mother carried the balanced translocation. In the mother’s blood culture inactivation of the X’s followed two modes: In 85 % of the cells the normal X was late replicating, and in the remaining 15 % the der(X) was inactivated, including the attached fragment of chromosome 6. The third translocation, t(X;17)(pll;q24), was found in three generations. In the phenotypically normal mother, who carried the balanced translocation, the late-replicating X was always the normal X. In her daughters, who had an unbalanced karyotype, 46, X, der(X), and multiple congenital abnormalities, the X part of the translocation chromosome was always late replicating. No spreading of inactivation over the attached autosomal region was observed, resulting for these patients in a partial trisomy of 17q. Their peculiar phenotype is described.
Differences in the order of termination of DNA replication in human chromosomes in peripheral blood lymphocytes and skin fibroblasts from the same individual
Authors: Farber R.A. , Davidson R.L.
Published: May 2008

A comparison of the sequence of terminal replication of DNA in human chromosomes has been made between skin fibroblasts and peripheral blood lymphocytes from the same adult male individual. The chromosomes were identified by quinacrine-banding, and the order of termination of replication was determined by autoradiography. Chromosomes 4, 5, 8, and 13 were found to terminate DNA replication later in lymphocytes than in fibroblasts, whereas chromosomes 15, 19, 20, and 22 were found to terminate their replication earlier in lymphocytes than in fibroblasts.
Mapping AK1 ACONs, and AK3 to chromosome 9 in man employing an X/9 translocation and somatic cell hybrids
Authors: Shows T.B. , Brown J.A.
Published: May 2008

The adenylate kinase1 (AK1), adenylate kinase3 (AK3), and aconitases (ACON3) genes have been assigned to chromosome 9 in man by employing an X/9 translocation segregating in man-mouse somatic cell hybrids. Segregation was controlled by taking advantage of the HAT/8-azaguanine selection-counterselection strategy directed at the X-linked HPRT locus. Assignment of AK1to chromosome 9 has suggested the assignment of the ABO blood-group locus and the nail-patella (Np) locus to 9, since both loci are linked to AK1by family studies.
Operator-assisted semi-automatic karyotyping of banded metaphases
Authors: Wulf H.C.
Published: May 2008

Computerized chromosome analyses have resulted in up to 25 % erroneous classifications, whereas a cytogenetically trained laboratory technician has an error rate of less than 0.1 % in the preparation of a karyotype. In the project reported here, computerized classification is eliminated, and, instead, the other steps of the analysis leading to the final karyotype are automated. In the instrument is a projection microscope, modified to project the image on paper before the operator. The slide is scanned on a motor-driven scanning table, in search of a suitable metaphase. The operator stops the scanning motor when a suitable metaphase comes into view. The individual chromosomes of the metaphase are then framed, using a view finder, and are identified, after which the chromosome number is entered on a keyboard. The instrument automatically ensures that, for each data entry, the framed chromosome is photographed in such a manner that the chromosome is placed in the proper location with the correct orientation in the karyotype. When all chromosomes have been identified, and the data have been keyed in, a photograph of the finished karyotype is presented. Marking the metaphase chromosomes on the paper, chromosomes are counted within 20 s. With conventional methods, a total chromosome analysis takes 3–6 h, but the above-described device requires 20–30 min.
Meiotic studies of translocations causing male sterility in the mouse
Authors: Forejt J. , Gregorová S.
Published: May 2008

A new meiotic phenomenon is described in male mice heterozygous for the male-sterile translocations T(10;13)199H, T(16;17)43H, and T(7;19)145H. The phenomenon consists of a nonrandom contact between the C bands of the X chromosome and the translocation configuration in diakinesis/metaphase I plates. Translocation configurations with positively heteropycnotic regions, often associated with the allocyclic X chromosome, are found in some early diakineses that have not been overtreated with alkali. Such heteropycnosis of a part of translocated autosome, apparently in phase with the allocyclic X, is typical for all three male-sterile translocations. In contrast to these findings, neither nonrandom contacts nor positive heteropycnosis of the translocation configuration can be found in males heterozygous for the translocation T(9;17)138Ca, which does not impair spermatogenesis. Dissociation of the X and Y at diakinesis is significantly enhanced in sterile males, though the occurrence of dissociation is evidently not related to the presence of the C-band contact between translocated chromosomes and the X. A working hypothesis is proposed, relating the observed nonrandom C-band contact and heteropycnosis of translocated chromosomes to a presumed impairment of X inactivation in primary spermatocytes and to consequent failure of spermatogenesis. An alternative explanation cannot be excluded, however, which would account for the hitherto available data without postulating any causal relationship between the meiotic findings and male sterility. Both alternatives are amenable to experimental verification.
Identification of nucleolus organizer regions (NORs) in normal and neoplastic human cells by the silver-staining technique
Authors: Hubbell H.R. , Hsu T.C.
Published: May 2008

Silver nitrate has been used to demonstrate the chromosomal location of ribo-somal cistrons in nine tissue-culture lines derived from human tumors of various pathological origins. Control individuals have a particular modal number (range 7–10) of D- and G-group chromosomes stained with silver. In the controls, 96.2 % > of the D- and G-group chromosomes that have a stalk show silver staining, while no relationship can be seen in acrocentric chromosomes without stalks. The tumor cells, whose modal chromosome numbers range from 42 to 68, possess variable numbers of acrocentrics (11–18). The number of chromosomes stained with silver, however, remained at control levels (range, 6–9). These data indicate that, in humans, silver staining may not identify all NORs that contain structural ribosomal genes.
Gene dose effect: intraband mapping of the LDH A locus using cells from four individuals with different interstitial deletions of 11p
Authors: Francke U. , George D.L. , Brown M.G. , Riccardi V.M.
Published: May 2008

The quantitative expression of LDH A was studied in hemolysates from four patients with different but overlapping interstitial deletions of the short arm of chromosome 11. Deficiency of LDH A was demonstrated in one patient, and the LDH A locus has been assigned to that segment of lip for which this patient alone was deficient, i.e., to band llpl2 (region 11p1203→11p1208).
Estimation of the sizes of polymorphic C-bands in man by measurement of DNA content of whole chromosomes
Authors: Sumner A.T.
Published: May 2008

A method is proposed for estimating the sizes of polymorphic C-bands of human chromosomes by microdensitometric measurement of the DNA content of whole chromosomes. The method requires measurements of: a chromosome known not to be polymorphic, as a standard against which to normalize all measurements; the polymorphic chromosomes of interest; and a homologous polymorphic chromosome lacking the C-band. In an example studied here, the C-band of chromosome 9 was estimated to contain about 0.0296 pg of DNA.
Assignment of the genes for human β-glucuronidase and mitochondrial malate dehydrogenase to the region pter→q22 of chromosome 7
Authors: Benn P. , Chern C.J. , Bruns G. , Craig I.W. , Croce C.M.
Published: May 2008

In human fibroblast cultures derived from adults, clones of cells with a common chromosome rearrangement have been widely reported. Cells derived from one of these clones have been used in hybridization experiments using mouse cells to localize the genes for β-glucuronidase and mitochondrial malate dehydrogenase on human chromosome 7. The results of this study indicate that the genes for these isozymes are located on the region pter→q22 of human chromosome 7.
The chromosomal location of rDNA in selected lower primates
Authors: Henderson A.S. , Warburton D.W. , Megraw-Ripley S.M. , Atwood K.C.
Published: May 2008

Hybridization in situ was used to identify the chromosomes that carry rDNA in representative lower primates, including the baboons, Papio cynocephalus and Papio hamadryas; the colobus monkey, Colobus polykomos; the tree shrew, Tupaia glis; the lemur, Lemur †ulvis; the saki, Pithecia pithecia; the marmoset, Saguinus nigricollis, and the spider monkey, Ateles geoffroyi. The marker chromosome, common to the Cercopithecines studied to date, carries the rDNA in the baboons. Another marker chromosome carries rDNA in a South American species, the spider monkey. A multichromosomal distribution of rDNA was demonstrated in the tree shrew, lemur, saki, and marmoset. None of the rDNA-containing chromosomes in the prosimians and New World monkeys show homology to the chromosomes that carry rDNA in the Hominids, Pongids, or Old World monkeys.
Chromosome replication patterns in an established cell line (CHO)
Authors: Campbell C.E. , Worton R.G.
Published: May 2008

The chromosome replication patterns of the established cell line CHO have been examined and compared with those of normal primary Chinese hamster cells, using the BudR-Hoechst fluorescence technique developed by Latt (1973). The results of this study indicate that the majority of CHO chromosomes replicate normally. There are four clear-cut exceptions to this rule, three of which are most easily explained as undetected or misinterpreted structural rearrangements of the CHO genome. Several other regions may also replicate differently in CHO and normal primary Chinese hamster cells, but uncertainties in the technique do not allow us to confirm this.
Random arrangement of mitotic chromosomes in radial metaphases of the Indian muntjac
Authors: Korf B.R. , Diacumakos E.G.
Published: May 2008

The positioning of metaphase chromosomes of the Indian muntjac (Muntiacus muntjak) in the radial metaphase array was investigated using two methods for examining cells. Large numbers of radial metaphase figures were obtained by mitotic shake-off. Treatment with hypotonic solution, fixation, and spreading onto glass slides did not disrupt the radial metaphase configuration of a proportion of the cells. Analysis of 567 cells for the arrangement of six of the seven muntjac chromosomes revealed a random positioning of each chromosome within the radial array. These results were corroborated by results obtained from 101 living cells oriented with microneedles to enable examination of radial metaphases with phase-contrast microscopy.
The karyotype of the tetraploid species Xenopus vestitus Laurent (Anura: Pipidae)
Authors: Tymowska J. , Fischberg M. , Tinsley R.C.
Published: May 2008

Xenopus vestitus possesses 72 chromosomes, whereas in the majority of known Xenopus species there are 2n = 36. During meiosis, 36 bivalents are usually observed at metaphase I and 36 chromosomes at metaphase II. Arranged according to size and centromere position, the chromosomes form the same basic morphologic groups typical of the genus Xenopus. However, the groups are composed of quartets of four similar chromosomes instead of diploid pairs of homologs. The exception to this arrangement involves chromosomes bearing secondary constrictions, which in X. vestitus are represented by two different pairs of homologs, one of which shows, in 39 % of the observed mitoses, somatic association and is, therefore, considered to carry the nucleolar organizer. X. vestitus represents either a case of ancient autotetraploidy or, more likely, one of allotetraploidy of more modern origin.
A new chromosome type replacing the double minutes in a mouse tumor
Authors: Levan A. , Levan G. , Mandahl N.
Published: May 2008

For several years the SEWA mouse ascites tumor has been a carrier of double minute chromosomes (DMs), some 90 % of its cells containing from one to several hundred DMs. In one specific subline of this tumor, the cells with DMs had decreased in frequency to less than 5 % of the cells. At the same time, the stemline chromosome number had increased from 43 to around 50. This was due to the presence, in addition to the ordinary telocentric chromosomes, of a varying number of medium-sized metacentrics. The fact that these chromosomes deviated from ordinary mouse chromosomes in special features, such as median centromeric position, early DNA replication, and complete lack of centromeric heterochromatin, indicates that they represent a new type of chromosome. Their striking agreement with the DMs in many properties makes it tempting to associate their origin with the disappearance of the DMs.