bluuebunny/crossref_metadata_2025 huggingface dataset:
Normal Karotype/Translocation Mosaic
Authors: Schmid W. , Hatfield D.
Published: April 2008

Cultured blood cells of an 86-year-old healthy woman displayed a chromosomal mosaic. A large proportion of the cells exhibited an identical abnormal karyotype, most likely the result of a translocation between a number 2 chromosome and a long acrocentric. The mode of origin of the aberration, and possible similarities in the developmental pattern that this mosaicism shares with leukemias and Waldenström’s macroglobulinaemia are discussed.
Further Observations on Marrow Chimerism in Marmosets
Authors: Benirschke K. , Brownhill Lydia E.
Published: April 2008

Five species of the family Hapalidae were studied for the presence of marrow chimerism. In six of fourteen animals heterosexual cells were found in the bone marrow. Four species had a chromosome complement of 2 n = 46 while the pygmy marmoset (Cebuella pygmaed) is characterized by 2 n = 44. On morphologic grounds it may be presumed that the additional large metacentric element of the pygmy arose through centric fusion of small acrocentrics. Differences exist in the morphology of the karyotypes in these species, particularly with respect to the smaller elements and Y. Tissue cultures prepared from lung and kidney in three marrow chimerae contained no heterosexual cells. Two female animals with substantial marrow chimerism had normal external and internal genital tracts.
The Somatic Chromosomes of Some Primates (Tupaia glis, Nycticebus coucang, Tarsius bancanus, Cercocebus aterrimus, Symphalangus syndactylus)
Authors: Klinger H.P.
Published: April 2008

Chromosome counts and karyotype data are presented for five primates Tupaiaglis (Common tree shrew) has 62 chromosomes, 12 metacentric and 48 acrocentric autosomes, a metacentric X and acrocentric Y. Nycticehus coucang (Slow loris) has 5·chromosomes all of which including the X and Y, are metacentric. Tarsius bancanus (Horsfield’s tarsier) has 80 chromosomes, the highest number recorded for any mammal, 14 are metacentric and 66 are acrocentric. Since only a female could be studied the sex chromosomes were not identified. Cercocebus aterrimus (Black mangabey) has 42 chromosomes of which all, including the X and Y, are metacentric. Symphalangus syndactylus (Siamang) has 50 chromosomes of which 48, including the X and Y are metacentric and 2 are acrocentric. The karyotype of this species is compared with that of Hylobates lar (White-handed gibbon). These findings support the trend observed by others that within an order species with high chromosome numbers have many acrocentrics and those with low numbers have more metacentrics. This suggests that structural rearrangements may have played a large role in evolution. Whether more “specialized” forms have primarily acrocentric chromosomes and “generalized” forms less is discussed. It is concluded that more data is required to verify both of these hypotheses.
Non-Random Distribution of Chromosomes in Metaphase Figures from Cultured Human Leucocytes. II. The Peripheral Location of Chromosomes 13, 17–18 and 21
Authors: Miller O.J. , Breg W.R. , Mukherjee B.B. , Van N. Gamble A. , Christakos A.C.
Published: April 2008

Two collections of XY-containing karyotypes were screened to obtain every karyotype in which the Y chromosome was distinguishable from the other small acrocentric chromosomes. The metaphase figures corresponding to these karyotypes were then examined, and approximately one-fourth of these were discarded because of marked distortion of the chromosome spread. The 37 remaining metaphase figures, 22 from the Columbia-Presbyterian collection and 15 from the Southbury collection were used to study the frequency of peripheral location of specific chromosomes. Five circular metaphase figures from each collection were selected for measurement of the distance of specific chromosomes from the center. In each collection the five metaphase figures were of similar area, but the Southbury metaphase figures were approximately 25 per cent larger in area than the Columbia-Presbyterian metaphase figures. All metaphase figures were obtained by flattening cells from human leucocytes cultures that had been treated with colchicine and hypotonic sodium citrate prior to fixation.
DNA Replication Patterns of Human Chromosomes
Authors: Schmid W.
Published: April 2008

Autoradiographic studies of human chromosomes labeled with tritiated thymidine have been carried out on cells from 15 individuals with normal and abnormal karyotypes. The labeling method that was applied is based on the observation that, in the late part of the DNA synthetic period (S-period), specific, large chromosome segments complete DNA replication at different time intervals. The DNA replication patterns are reported as they were observed, for individual chromosome pairs, during the last two hours of the S-period. It is demonstrated that the method has become a useful tool for chromosome identification and characterization, and a detailed description of the techniques used, is given. Secondary constrictions in certain chromosome pairs which have been demonstrated by means of special techniques (Sasaki and Makino, 1963; Saksela and Moorhead, 1962) are shown to coincide with specific, late DNA replicating chromosome regions.
A Case of XXXXY Sex Chromosome Anomaly with Autoradiographic Studies
Authors: Atkins L. , Böök J.A. , Gustavson K.-H. , Hansson O. , Hjelm M.
Published: April 2008

A 21-month-old boy with multiple congenital anomalies was found to have 49 chromosomes with an XXXXY sex chromosome constitution. He was mentally retarded with skeletal abnormalities, hypertelorism, malformed and asymmetrical ears, a short broad neck and small external genitalia. A testicular biopsy specimen showed defective germ cell and tubule development. Autoradiographic studies with tritiated thymidine showed asynchrony in DNA synthesis of the chromosomes of cultured skin and testis cells. In cells labelled late during the DNA synthetic period three heavily labelled X chromosomes were demonstrated. Autoradiographs of interphase nuclei derived from the same cultures showed localized labelling of heterochromatic foci, including the sex chromatin, in a small percentage of cells. The results are interpreted as evidence for the derivation of a sex chromatin body from an entire X chromosome which replicates late during the DNA synthetic period.
The Specific Effects of Streptonigrin Activity on Human Chromosomes in Culture
Authors: Cohen M.M.
Published: April 2008

The distribution of chromosome breaks induced by streptonigrin (SN) and X-ray in chromosomes Nos. 1, 2, and 3 of cultured human leukocytes was investigated. In all chromosomes tested, the breaks caused by X-ray were randomly distributed both among and within the chromosomes in proportion to their relative lengths. SN, however, produced significant non-random distributions of breaks in chromosomes No. 1 and No. 2. The pericentric regions of chromosomes No. 1 and No. 2, as well as the secondary constriction area in the long arm of No. 1, seemed highly susceptible to breakage. Although SN produced significantly fewer breaks than expected in chromosome No. 3, these breaks were randomly distributed along its length. The telomere regions of all chromosomes and the short arm of chromosome No. 2 appeared to be relatively resistant to the action of SN.
A Mentally Defective Male with Klinefelter’s Syndrome and Probable XXYY/XXY Mosaicism
Authors: Bergman S. , Bjersing L. , Reitalu J.
Published: April 2008

A main karyotype of 48/XXYY was found in a mentally defective male patient with clinical signs of Klinefelter’s syndrome. 3.4% of the cells were XXY, thetefore the patient is thought to be an XXYY/XXY mosaic. The interpretation of the extra chromosome as a Y seems most likely, but some other possibilities are also discussed.
Heterosexual Cells in Testes of Chimeric Marmoset Monkeys
Authors: Benirschke K. , Brownhill Lydia E.
Published: April 2008

The testes of three marmoset monkeys in whom a percentage of marrow cells was found to be derived from a female co-twin were studied. In two of the animals some XX mitoses of presumed spermatogonial origin were present. After delineation of the XY bivalent in first meiotic metaphases, some cells were found in two animals in which no XY bivalent could be identified. These findings are interpreted to support the suggestion by Ohno et al. (1962), that germ cells occasionally reach the circulation of mammalian embryos and may be distributed to the gonads of co-twins.
Replication Patterns of Bovine Sex Chromosomes in Cell Culture
Authors: Gartler S.M. , Burt Barbara
Published: April 2008

A study of sex chromosome replication in euploid bovine cell cultures is presented. Both X chromosomes in the female replicate their DNA throughout most of the cell’s DNA synthetic period. However, one X (late X) continues its replication later than its homologue (early X). This late X is one of the last chromosomes in the complement to terminate replication. In the male, the DNA replication pattern of the X chromosome is like that of the early X in the female, while the Y chromosome begins its replication later than any chromosome in the complement (by two or more hours), and finishes replication just after the X.
Maturation Division in Bovine Oocytes Following Gonadotropin Injections
Authors: Hafez E.S.E. , Ishibashi I.
Published: April 2008

The maturation division of oocytes has been studied in relation to estrus, and follicle diameter in gonadotropin-treated and untreated beef cattle. Injection of pregnant mare serum (PMS) gonadotropin had no effect on the pattern of maturation division of oocytes. The follicles reached full size shortly before the onset of estrus. During early estrus, all oocytes had nuclei of metaphase I; the maturation division rapidly progressed to metaphase II during late stages of estrus. Human chorionic gonadotropin (HCG) treatment which has been recognized to be effective for stimulating ovulation did not affect the pattern of maturation division of the oocytes. Degeneration of oocytes occurred in all stages of follicular maturation during and following estrus, irrespective of the follicle size.
A D/F Translocation in a Case of Regular Trisomy 21 Down’s Syndrome
Authors: Gripenberg Ulla , Airaksinen Eila
Published: April 2008

A girl aged 9 months with clinical symptoms of Down’s syndrome had 47 chromosomes in preparations from peripheral blood leucocytes. An unusual karyotype was found with abnormal distributions of chromosomes in the following groups: C:17, D:5, F:3 and G:6. The interpretation of the karyotype is based on the assumption that there is a simultaneous occurrence of trisomy in group G and a translocation between chromosomes of group D and F. The mechanism to which these deviations are attributable is discussed. A causal relationship between trisomy and translocation is suggested.
Clinical and Cytogenetical Studies in Female Gonadal Dysgenesis and Their Bearing on the Cause of Turner’s Syndrome
Authors: Ferguson-Smith M.A. , Alexander D.S. , Bowen P. , Goodman R.M. , Kaufmann B.N. , Jones, Jr. H.W. , Heller R.H.
Published: April 2008

Clinical and chromosomal studies are reported for 30 female patients selected because they show at least one of the characteristic features of Turner’s syndrome. Exploratory laparotomy has been performed in eight patients, and culdoscopy in two others. Seven patients have an XO sex chromosome constitution, eight have XO/XX mosaicism, two have probable XO/XX/XXX mosai-cism, one has XX1, five have XO/XXi mosaicism, one has a presumptive deletion of the long arm of an X chromosome, two have small structural X or Y chromosome aberrations, one has XO/XY mosaicism and three have an apparently normal XX karyotype. Xg grouping in one XO patient and her parents reveals that the X chromosome may be maternally derived, and similar studies in one X isochromosome-X patient suggest that the isochromosome-X may be paternally derived. Parental age was found to be normal. Sex chromatin findings in the patients with an isochromosome-X, and in a patient with an X-deletion, confirm that the structurally abnormal X forms the sex chromatin body. Karyotype-phenotype correlations in these, and in previously reported patients, support the hypothesis that the usual cause of Turner’s syndrome and its variants is variable deficiency of the X and Y chromosomes, due both to mosaicism and to deletion involving postulated homologous loci. “Streak” gonads are the usual consequence of a large deficiency of any part of the X, but the marked short stature and associated stigmaa of Turner’s syndrome are only observed in cases where the deficiency includes the short arm of the X (including the pairing segment) or part of the Y. The karyotype-phenotype correlations support the concept that a part of the short arm of both X chromosomes is genetically active in human female somatic cells.
A Very Large Metacentric Chromosome in a Woman with Symptoms of Turner’s Syndrome
Authors: Wie Lie Gouw , Coenegracht J.M. , Stalder G.
Published: April 2008

A sex chromatin positive woman has stunted growth, primary amenor-rhoea, cubitus valgus, Madelung’s deformity and mental deficiency. A modal chromosome number of 46 was found in cultures from peripheral blood, skin and Fascia lata, but an abnormal very large metacentric chromosome and only 15 chromosomes in the X-6–12 group were observed in karyotypes from cells of all cultures. Large and characteristic bipartite bodies were often present in buccal and vaginal smears, and the size of the polymorphonuclear drumsticks was increased. Autoradiographically the abnormal chromosome was the only “hot” chromosome. The patient was Xga negative although her father was Xga positive. We conclude that the unpaired large chromosome in our patient is an abnormal X chromosome with a partial deletion and a translocation of a piece of an autosome or sex chromosome onto its short arm.
Constancy of Nuclear DNA and Accuracy of Cytophotometric Measurement
Authors: James J.
Published: April 2008

When sources of error of preparative and optical nature are avoided, a very high degree of accuracy can be attained by scanning photometry of Feulgen-stained and adequately flattened cell nuclei. In tetraploid rat liver nuclei, the spread observed in readings of different nuclei and of one nucleus in different positions to the optical axis is virtually the same, with a variation coefficient of below 1 %.
Chromosomes of the Ground Squirrel Spermophilus beldingi and Report of an Aberrant Karyotype in a Phenotypically Normal Female
Authors: Nadler C.F.
Published: April 2008

Mitotic chromosomes were analyzed from two subspecies of the ground squirrel, Spermophihts beldingi. S. beldingi oregonus and S. beldingi crebrus each had a diploid chromosome number of thirty and their karyotypes were similar. Chromosomal characters from these subspecies were similar to the characters reported in S. beldingi beldingi. Chromosomal characters support the current taxonomic opinion that beldingi, oregonus and crebrus are valid subspecies of S. beldingi. One phenotypically normal S. beldingi oregonus female had an aberrant karyotype that contained an unpaired submetacentric and a minute metacentric chromosome. The significance of the aberration is discussed.
Chromosome Replication Pattern in an Established Bovine Cell Line
Authors: Gartler S.M. , Burt Barbara
Published: April 2008

A study of chromosome replication in an established bovine male cell line (MDBK) is presented. In this line the Y chromosome is no longer present as an independent structure and a new marker chromosome is present. Morphological evidence suggests that this marker chromosome may have resulted from a fusion of the Y and a large acrocentric chromosome. Chromosome replication studies show that the suspected Y part of the marker chromosome has a DNA replication pattern very similar to that of the Y chromosome in normal cells.
Post-Zygotic Chromosomal Rearrangements in Rainbow Trout (Salmo irideus Gibbons)
Authors: Ohno S. , Stenius C. , Faisst E. , Zenzes M.T.
Published: April 2008

Four age groups of the rainbow trout (Salmo irideus) were surveyed in an extensive cytological study. While the basic diploid complement of this species was found to consist of 104 chromosome arms, some elements united and dissociated early in embryonic life; thus within each individual fish, from two to seven distinct chromosome constitutions were identified, ranging from 2n = 58 to 2n = 65. Each somatic cell type tended to have a particular diploid chromosome number. Several multivalents were found in meiotic germ cells of both sexes. The Robertsonian type of chromosomal change which played an important part in the evolution of terrestrial vertebrates is seen within single individuals of this teleost fish.
Cytogenetics of Down’s Syndrome (Mongolism) I. Data on a Consecutive Series of Patients Referred for Genetic Counselling and Diagnosis
Authors: Hamerton J.L. , Giannelli F. , Polani P.E.
Published: April 2008

The chromosome findings in a series of 173 Down’s syndrome or presumptive Down’s syndrome index patients, and a further 3 5 pairs of parents of Down’s syndrome index cases, are given. One hundred and forty-four index cases had primary G21 trisomy; six were interchange trisomics, six were mosaics, and one was a chromatin positive male with XXY sex chromosomes and primary G21 trisomy. Sixteen index patients whose diagnosis could not be clinically confirmed, were found to have normal chromosomes. The 35 pairs of parents all had normal chromosomes. In seven families (three index patients with primary G21 trisomy, two with normal chromosomes and two index patients not studied) minor morphological chromosome anomalies were observed. The relevance of this data to the causal association of Down’s syndrome and G21 trisomy, the frequency of mosaicism, double trisomy and association with other chromosome anomalies, is discussed.
An Autoradiographic Study of DNA Synthesis in the Sex Chromosomes of Two Marsupials with an XX/XY1Y2Sex Chromosome Mechanism
Authors: Hayman D.L. , Martin P.G.
Published: April 2008

Potorous tridactylus and Protemnodon bicolor are marsupial species in which the sex chromosome system is XX/XY1Y2. Nearly all the long arm of the X is homologous with the Y2; the short arm of the X is unpaired in the male. During the last part of DNA synthesis in females only the short arm of one of the 2 X-chromosomes shows asynchronous synthesis of DNA. The long arm sof the X’s and homologous autosomes synthesize DNA synchronously. Some pairs of non-homologous autosomes synthesize asynchronously. The implications of this in terms of the Lyon hypothesis and the evolution of X-chromosomes are discussed.
A Method for Meiotic Preparations of Mammalian Ova
Authors: Jagiello Georgiana M.
Published: April 2008

Superovulation is induced in the female rodent with a priming dose of PMS followed by an ovulating dose of HCG. At proper time intervals thereafter, follicular or ductal ova can be obtained in large numbers, freed of coronal cells while in a 0.7 % sodium citrate solution and fixed in 50 % acetic acid. Freezing with dry ice and methanol permits removal of the cover slip after mild squashing and the dried preparation can then be hydrolysed with in HCL and stained with Giemsa stain. Preparations of good quality which permit examination of number and morphology of the chromosomes of ova in first or second meiotic metaphase can thus be obtained.
Secondary Constrictions in Human Chromosomes
Authors: Palmer Catherine G. , Funderburk Sandra
Published: April 2008

Human leukocyte cultures have been studied for the location of secondary constrictions and their frequency of occurrence. The constrictions appear most frequently in chromosomes 9 and 1, less frequently in 2, 4L, 6L, 11, 13, 16 and rarely in 3, 5L, 6S, 17, 19 and 21. In general, only one homolog bears the constriction with the exception of numbers 9 and 1. The concentration of mitotic accumulating agent appears to affect the occurrence of secondary constrictions. Cultures treated with 5-bromodeoxyuridine show many of the normally-occurring constrictions and in addition other regularly-occurring morphological markers of a similar nature.
DNA Replication Patterns in Somatic and Germ-line Cells of the Male Chinese Hamster
Authors: Utakoji T. , Hsu T.C.
Published: April 2008

DNA replication patterns in bone marrow (somatic) and spermatogonial (gonadal) cells of the Chinese hamster were studied with autoradiographic methods. The generation time of bone marrow cells was approximately 10 h, and the G2 phase was less than 2 h. The DNA replication sequence in bone marrow cells was similar to that of somatic cells in tissue culture, i.e., the long arm of the X and the entire Y replicate in late S, but not in early S phase. The average G2 phase of the spermatogonia was approximately 6 h. Its DNA replication sequence was different from that of the somatic cells. The long arm of the X and the entire Y were not labeled in late S phase. The late labeling pattern of autosomes resembled that of the somatic cells. Since the heteropycnosis, late DNA replication, and genetic inactivation appear closely related, the DNA replication sequence of spermatogonial cells suggests that the sex chromosomes are metabolically active, at least in some stages of germ cell development.
The Mitotic Chromosomes in Xenopus laevis (Daudin): Normal, Sex Reversed and Female WW
Authors: Mikamo K. , Witschi E.
Published: April 2008

A chromosome study in Xenopus laeυis with five of the six possible male and female sex combinations of the ZZ, ZW and WW genie constitutions furnishes no visible evidence of sex chromosome dimorphism. This conclusion is based on construction and analysis of 71 karyotypes of somatic or spermatogonial cells, of which 31 are of ZZ, 29 of ZW and 11 of WW genetic constitution. The constitution of the twenty donor animals is certified by their breeding records. The morphologic study reveals that the 36 chromosomes of this species can be arranged in a series of 11 submetacentric and another series of 7 subacrocentric chromosomes. The chromosome pairs of all genetic types consist of visually equal partners (homomorphic pairs). Measurement of the overall lengths of all chromosomes (in relative units) and calculation of arm ratios do not reveal differences between genetic types nor furnish any indication of the presence of a heteromorphic Z-W pair. Testicular and ovarian development with complete spermatogenesis and ovogenesis proceed normally with any of the three genie types.
Sex Chromatin in Somatic Cells of the Philander opossum quica(TEMMINCK, 1827, Marsupialia)
Authors: Perondini A.L.P. , Perondini Dulcinéa R.
Published: April 2008

In both sexes the Brazilian marsupial Philander opossum quica (Temminck, 1827) presents one conspicuous chromocenter in its somatic cells at interphase. The sex chromatin body in males is about half the size of the sex chromatin in females. A small, positively heteropycnotic chromosome is seen at prophase, prometaphase and metaphase in both sexes; in males it is half the size of the heteropycnotic chromosome seen in females. The sex chromosomes in this animal are the smallest in the karyotype and the Y chromosome is half the size of the X chromosome. It is concluded that in this species the sex chromatin body is formed by one condensed X chromosome in females and by the condensed Y chromosome in males.
A New Cytogenetic Variant of Translocation Down’s Syndrome
Authors: Aarskog D.
Published: April 2008

Chromosome studies in a child with Down’s syndrome revealed 47 chromosomes and only four small acrocentrics. The odd chromosome was a small almost metacentric chromosome of the same length as those in group F. In addition one of the chromosomes of the B group (presumably number 5) showed a deletion of a portion of the short arm. The findings are interpreted as a translocation involving a G chromosome and a part of the short arm of a chromosome in the B group.
Autosomal Polymorphism via a Translocation in the Guinea Pig, Cavia porcellus L.
Authors: Cohen M.M. , Pinsky L.
Published: April 2008

The karyotype of the guinea pig, C. porcellus L. was investigated using chromosomal preparations from various tissues of 15 animals (nine females and six males). The diploid number is 2N = 64. Only four large autosomal pairs and the X chromosome are individually identifiable. One entire X chromosome and possibly the short arms of the second X in females show late DNA replication. A polymorphism involving the short arms of the longest pair of autosomes is present in this population and this polymorphism is shown to segregate in families.
Variation in Chromosome Number Among European Wild Pigs
Authors: McFee A.F. , Banner M.W. , Rary J.M.
Published: April 2008

Peripheral leukocyte cultures from 36 European wild pigs have shown that 73% of the animals possessed 36 chromosomes while 27% had 37. Karyo-types of 36-chromosome individuals differed from those of domestic swine in that they possessed one pair of submetacentric chromosomes not found in domestic pigs and lacked two pairs of the domestic’s telocentrics. The 37-chromo-some animals had one chromosome of each of these three pairs but lacked their homologous members. Matings between animals with 36 and 38 chromosomes have produced fertile offspring with 37. A single litter from a 36 x 37 mating consisted of three pigs with 36 and three with 37 chromosomes, while one from a 37 x 37 mating contained progeny with 36, 37, or 38 chromosomes. The odd number of chromosomes in some wild pigs is postulated to have resulted from the entry of domestic breeding into the wild herd.
Alternative DNA Replication Patterns Associated with Long Arm Length of Chromosomes 4 and 5 in the Cri du Chat Syndrome
Authors: Miller O.J. , Breg W.R. , Warburton Dorothy , Miller Dorothym A. , Firschein I.L. , Hirschhorn K.
Published: April 2008

Autoradiographic studies of cultured leucocytes from nine cases of the cri du chat syndrome have been carried out. The deleted chromosome 4 or 5 is early replicating in seven cases, late replicating in one case, and not clearly either, in the case of a ring chromosome 4 or 5. The long arms of the early replicating deleted chromosome are significantly shorter than the mean length of the late replicating chromosomes and the same length as the other early replicating chromosome. The simplest interpretation of these observations is that the deleted chromosome and the other early replicating chromosome are homologues. Since they have shorter long arms, they are probably chromosome 5. The long arms of the late replicating deleted chromosome are relatively long, suggesting that it may be chromosome 4. The phenotypes are similar in all nine cases and show no distinct relationship to the replication pattern or to the length of the long arm of the deleted chromosome.
Chromatin Bridges and Origin of Multinucleate Cells in a Bovine Testicular Cell Line
Authors: Nelson-Rees W.A. , Kniazeff A.J. , Darby, Jr. N.B.
Published: April 2008

In the course of cytological observations of a cell line of bovine testicular origin since its initiation, many chromatin bridges and binucleate cells were noticed following the apparently spontaneous occurrence of chromatid fragmentation and formation of dicentric chromosomes. Subsequently, the frequency of binucleate cells and their respective nuclear sizes were recorded from permanent slides of material of passages made prior to, during, and after the incidence of chromatid fragmentation. Since the frequency of binucleate cells rose simultaneously with that of the chromatin bridges, and since the same nuclear size was involved in most cases, the frequency of chromatin bridges was taken as an index of their contribution to the production of binucleate cells following the period of chromatid fragmentation.
The Identification of the Chromosomes of the D Group (13–15) Denver: An Autoradiographic and Measurement Study
Authors: Giannelli F. , Howlett R.M.
Published: April 2008

An autoradiographic and measurement analysis of the D group chromosomes of a normal woman, a woman heterozygote for an interchange between two non-homologous D chromosomes, and a girl with primary Dl trisomy has been described. It has been found that D chromosomes with different labelling patterns belong to discrete size classes. The longest pair of D chromosomes (No. 13) are the last to complete DNA synthesis and have a late synthesizing region in the distal part of the long arm. The pair of chromosomes of intermediate length (No. 14) are the second to complete DNA synthesis and show a region of late DNA synthesis in the short arm and proximal part of the long arm. The shortest chromosomes (No. 15) are the first to complete DNA synthesis. The interchange heterozygote has been proved to carry an interchange between two D chromosomes that fit the definitions given here for chromosomes 13 and 14. The chromosome responsible for theDi trisomy syndrome cannot be assigned to a size class, on the basis of the present evidence, and its identification still rests only on the results of autoradiographic analysis.
Pattern of DNA Replication in Chromosomes of the Dog
Authors: Brown R.C. , Castle Wilma L.K. , Huffines W.H. , Graham J.B.
Published: April 2008

The cell life cycle of canine bone marrow cells in vitro was found to be approximately 12 hours, with an estimated S-period of 6 hours. Chromosomal replication was studied throughout S-period. Easy identification of the X-chromosomes in the dog provided an excellent model for comparison of X-chromosome replication patterns. In the female dog the X-chromosomes were asynchronous in replication. Uniquely the late-replicating X-chromosome had delay in intense replication until near mid-S-period, and it continued replication later in S-period than the early-replicating X-chromosome. More frequently, small autosomes were replicating later in S-period than the late-replicating X-chromosome. The single X-chromosome in the male had a replication pattern like the early-replicating X-chromosome of the female. Some small autosomes in both male and female cells continued replication late in S-period. Sister-chromatid-exchange was observed in both autosomes and X-chromosomes.
H3-Uridine Autoradiography of Human Chromosomes
Authors: Comings D.E.
Published: April 2008

Human lymphocyte and fibroblast metaphase chromosomes were labeled immediately prior to mitosis with tritiated uridine to study the feasibility of utilizing autoradiography to localize areas of genetic activity. Specifically, two questions were investigated. 1. Are consistent patterns of RNA labeling detectable by H3-uridine autoradiography of metaphase chromosomes? 2. Does H3-uridine autoradiography of metaphase chromosomes detect the decreased rate of RNA synthesis by the inactive X chromosome? H3-uridine autoradiography of XX, XY, X isochromosome X, and XXXXY cells demonstrated localization of grains to metaphase chromosomes. There were, however, no consistent patterns of RNA labeling, and no decrease in the number of grains over the inactive X chromosomes. Incubation of cells with various compounds to stimulate or suppress RNA synthesis, or treatment of metaphase preparations with varying concentrations of ribonuclease, failed to accentuate any patterns of labeling. Female cells labeled with H3–5-uridine for five minutes showed a marked decrease in grains over the sex chromatin body. Cells pulse labeled with H3-5-uridine and chased with cold uridine for up to 48 hours, also showed localization of grains to metaphase chromosomes but no consistent patterns of labeling. These results indicate that in humans sufficient amounts of newly synthesized RNA do not remain on the metaphase chromosomes to allow autoradiographic localization of their sites of synthesis. What labeling does occur is the result of random, non-specific adherance of labeled RNA to metaphase chromosomes.
Siblings with Different Types of Chromosal Aberrations Due to D/E-Translocation of the Mother
Authors: Hauschteck Elisabeth , Mürset Gertrud , Prader A. , Bühler Erika
Published: April 2008

A woman of normal appearance had an abortion and gave birth to two mentally defective children with different malformations. A fourth pregnancy was interrupted legally. Features of the first child resemble those of the D trisomy syndrome and the second child has some characteristics in common with cases of E trisomy syndrome. The common symptoms are mental deficiency, short stature, flexion of the fingers and a mild scrotal abnormality. The chromosomes were examined in some members of the family. In the mother, it is presumed that one part of a chromosome of group D has been translocated to a chromosome 17, giving a large chromosome in the group C size range. The other fragment of the broken chromosome resembles the chromosomes of group G. The mother presumably has the normal, although rearranged, genetic material in each cell. The two children reflect the two possible types of partial D trisomy derivable from the mother’s karyotype. Child 1 has the large D/E translocation chromosome with only one chromosome 17. Child 2 has 47 chromosomes since the proximal part of the involved maternal chromosome D has been inherited as an extra chromosome. Since a reciprocal translocation is possibly involved, then child 2 may be trisomic not only for part of a D chromosome but also for a region of chromosome 17. The clinical picture supports this possibility. The karyotypes of the embryo and the mother are identical. The chromosomes are normal in the maternal grandmother and in the father of children 1 and 2. The chromosome number is 46 in a maternal aunt, but two out of 18 mitoses examined have an abnormal karyotype.
Prominent Secondary Constrictions in a Pseudodiploid Human Cell Line
Authors: Miles C.P. , O’Neill F.
Published: April 2008

RPMI 2650 is a pseudodiploid human cancer strain. The chromosomes frequently exhibit multiple prominent secondary constrictions and the constriction patterns appear to characterize particular homologs. Many of the constrictions are at sites previously specified in benign cells. However, some of the changes observed, especially in chromosomes designated 8, 9, and 10, have been hitherto undescribed in human cells.
Exceptional Meiotic Conditions in Oocytes of Ambystoma talpoideum, Triturus viridescens Xenopus laevis and Their Relation to the Origin of Spontaneous Heteroploidy
Authors: Humphries, Jr. A.A.
Published: April 2008

Ten exceptional secondary oocytes from three genera of the Amphibia (Ambystoma talpoideum, Triturus viridescens and Xenopus laevis) are described. Six oocytes contained a single meiotic spindle in metaphase II, with the diploid number of dyads. Since no polar bodies were observed on these eggs, their condition is probably the result of an aberration of the first meiotic division which resulted in failure of formation of the first polar body. Four oocytes contained two spindles. One of these probably originated as a binucleate oogonium, since two polar bodies were present, but the remaining three are probably the result of an abnormal first meiotic division, in which polar body formation did not occur. These observations give cytological support to previously suggested routes by which heteroploidy may originate.
Observations on the Chromosomal, Cytological and Anatomical Characteristics of 75 Human Conceptuses
Authors: Schlegel R.J. , Neu R.L. , Carneiro Leão J. , Farías Elvira , Aspillaga M.J. , Gardner L.I.
Published: April 2008

Chromosome studies were successfully carried out on histologically identified tissues from 30 of 67 spontaneously aborted and eight full term products of conception. The anatomical structure of the amnion and chorion was normal in the eight full term cases and in 27 of the aborted specimens, each of which was found to have a normal chromosome complement. In three aborted specimens there were placental abnormalities consisting of hydatidiform degeneration of the chorionic villi, chorionic cysts and arborizing amniotic polyps. Giant cells were scattered through the bases, stems and dilated tips of the amniotic polyps. These abnormal cases had triploid XXY/diploid XY, triploid XXX and triploid XYY karyotypes respectively. In one specimen cultured cells from both the amnion and the embryo yielded triploid XXX karyotypes. The mean nuclear diameter of triploid amnion cells was found to be significantly greater than that of diploid amnion cells (P = 0.001) in the fresh tissue state and in tissue culture.
The Duration of Replication of the Inactive X Chromosome in Humans Based on the Persistence of the Heterochromatic Sex Chromatin Body During DNA Synthesis
Authors: Comings D.E.
Published: April 2008

To determine the status of heterochromatin while it was undergoing DNA synthesis, human female fibroblasts were exposed for a brief period of time (three minutes) to tritiated thymidine and immediately fixed. Autoradiography demonstrated that the sex chromatin body retains its heterochromatic form during DNA replication. This was confirmed by the observation that the percentage of sex chromatin positive cells was not significantly different for cells in the S period of the cell cycle as compared with cells in the G1 or G2 period. The nature of the labeling differentiated three types of sex chromatin bodies: those that were unlabeled; those that labeled with a grain density equivalent to euchromatin (early labeled); and those that labeled with a grain density much greater than that of the surrounding euchromatin (late labeled). Of 138 cells, the sex chromatin was unlabeled in 34%; early labeled in 45%; late labeled in 21%. These fractions were multiplied by the duration of the S phase of DNA synthesis (7.5 hours) determined on the same culture of cells. This demonstrated that the inactive X chromosome does not begin DNA replication until 2.5 hours after the onset of replication of euchromatin. It then continues with an intensity of labeling equivalent to euchromatin for 3.4 hours, and continues replication for 1.6 hours after most euchromatin has ceased replication. The total duration of replication of the inactive X chromosome was approximately five hours, compared with over six hours for euchromatin. The implications of these observations in relation to histones, chromosome coiling, DNA and RNA synthesis, number of replicons in the nucleus and sex chromatin negative cells are discussed.
The Role of Sex Chromosome Chimerism in Altering Sexual Development of Mammals
Authors: Herschler M.S. , Fechheimer N.S.
Published: April 2008

Thirteen bovine females, twins to males, were examined in a study of the variability of the freemartin syndrome. The range of intersexuality was from foreshortened uterine horns in the least masculine to complete absence of Müllerian derivatives and development of accessory sex glands in the most masculine. Histological examination revealed no follicular development in the gonads, although juvenile ovarian stroma or testicular tissue or both were present in some. The animals were rated by the degree of masculinization of the reproductive system, which was found to be positively correlated (r = 0.70, p < 0.01) with the percentage of cells of male origin in cultures of peripheral blood from the freematins. The relevancy of these and other data to the general problem of sexual differentiation is discussed. It is concluded that the primary etiological factor of gonadal modification in freemartins is the presence of Y chromosome-bearing cells at the time of differentiation.
Replication Patterns of the Unpaired Chromosome No. 9 of the Rodent Ellobius lutescens Th.
Authors: Castro-Sierra E. , Wolf U.
Published: April 2008

Autoradiographic studies were done of DNA replication in the unpaired chromosome No. 9 of Eilobius lutescens. The replication sequence is identical in both sexes. The unpaired chromosome comprises approximately 5 % of the haploid complement, corresponding to the original-type X chromosome in the majority of placental mammals. The relation of the odd chromosome to the sex-determining mechanism of this species is discussed.
New Karyotypic Data on 15 Genera of Lizards in the Family Iguanidae, With a Discussion of axonomic and Cytological Implications
Authors: Gorman G.C. , Atkins L. , Holzinger T.
Published: April 2008

Karyotypic data are presented for 14 species of iguanid lizards assigned to 14 genera and for 9 species of iguanids in the genus Anolis. A basic chromosomal formula of six pairs of large metacentric chromosomes and 12 pairs of microchromosomes characterizes many of the representatives of the family: Oplurus sebae from Madagascar; eight species of Anolis; the anoline species Anisokpis grilli; the large iguanines Ctenosaura pectinata, Cyclura cornuta, Iguana iguana and Sauromalus obesus; the basiliscine Basiliscus vittatus; and two tropidurines, Tropidurus torquatus and L·eiocephalus schreibersi. Within the tropidurines there has been chromosome evolution. Liolaemus lutzae has only 11 pairs of microchromosomes, the largest of which is considerably larger than the others and probably represents centric fusion from the original 12 pairs. Plica plica differs from the other tropidurines and all other iguanids examined in having eight pairs of macrochromosomes – four metacentric pairs and four acrocentric pairs. Evidence is presented to show that this is a condition derived from six pairs of metacentrics. The sceloporine Uma notata is characterized by six pairs of metacentric macrochromosomes and 11 pairs of microchromosomes. A reduced number of microchromosomes from the presumably primitive number of 12 also characterizes all other sceloporines listed in the literature. Cupriguanus achalensis, a recently described genus and species, also has 12 macrochromosomes and 24 microchromosomes. The largest pair of microchromosomes appears heteromorphic in the male. Anolis auratus has seven pairs of macrochromosomes and eight pairs of microchromosomes; this is typical of the group within Anolis to which it belongs. This species is a beta Anolis, a group that was characterized in the literature as having seven pairs of metacentric macrochromosomes. The other major subgroup of Anolis has the more typical six pairs of macrochromosomes. One species of iguanid, Polychrus marmoratus has a karyotype so different from the remainder of the family that it is impossible to assess its relationship. There are 20 acrocentric chromosomes and ten microchromosomes in the female. In male meiosis there are 14 bodies, 13 bivalents and a presumed sex trivalent. The diploid number is 29;
Chromosome Abnormalities in Lymphocytes from Normal Human Subjects
Authors: Lubs H.A. , Samuelson J.
Published: April 2008

The occurrence of chromosome gaps, breaks and rearrangements was determined in 3,720 lymphocyte metaphases obtained from ten normal adults. The frequency of the cells with one or more breaks varied from 1–20%, and the maximum variation found in one individual during sequential cultures was 6–20%. Multiple breaks were found in only 17 cells, and a structural rearrangement (translocation, dicentric inversion or triradial configuration) occurred in eight cells. Chromatid breaks were not randomly distributed, occurring most frequently as subterminal breaks in the long arm of No. 16 in both sexes and the short arm of the No. 3 in females. Previous studies demonstrating an increased number of breaks in these areas following treatment with a variety of agents may be best explained by an accentuation of the normally occurring pattern of breaks.
The Identification of the Chromosomes of the E Group (16–18 Denver): An Autoradiographic and Measurement Study
Authors: Giannelli F. , Howlett R.M.
Published: April 2008

An attempt has been made to classify the E chromosomes of four subjects with an abnormal chromosome complement using two criteria: the autoradiographic grain counts in cells labelled towards the end of the DNA synthetic period and a ‘morphological index’. This was found to be a better discriminant than the total length and was obtained by dividing the arm ratio of each chromosome into its total length. The first patient, a girl heterozygous for a presumptive deletion of the long arm of the X chromosome, had only 15 chromosomes in the C group and seven in the E group. One of these, which had a very high morphological index, was by far the most densely labelled and was therefore identified as the abnormal X chromosome. The other six chromosomes could be sorted into a pair with high index (No. 16) and a group of four which could be further subdivided into a pair with low grain counts and intermediate index (No. 17) and a pair of high grain counts and low index (No. 18). The second patient had a ring chromosome for one of the E chromosomes. The patient’s five normal E chromosomes could be divided into a pair with high and a pair with low morphological index, while the fifth chromosome had an intermediate value. This chromosome had a mean grain count similar to that of the ring chromosome and lower than that of any other E chromosome. It was therefore concluded that this patient was heterozygous for a No. 17 ring chromosome. The results obtained in this patient clearly showed that, in this group, morphologically similar chromosomes (presumptive homologues) have similar grain counts. The last two patients had similar abnormal phenotypes, and both were heterozygous for a deletion of the short arm of one of the E chromosomes. The five normal E chromosomes of these patients could not be sorted into pairs by the separate analysis of the morphological index and grain counts. However, they could be divided into a sub set of three chromosomes with grain counts as high or higher than that of the deleted chromosome, which should have included the homologue of the abnormal E chromosome, and a sub set of two chromosomes with lower grain counts. The study of the morphological index of the first group clearly showed that two chromosomes with a high morphological index formed a pair, while the third chromosome had a low index and was unpaired. An analysis of the grain counts over the normal E chromosomes confirmed that the chromosome with the lowest index was unpaired in both patients. It was therefore concluded that they were heterozygous for a deletion of the short arm of chromosome No. 18.
Opossum lymphocytes in vitro: a valuable tool for cytogenetic investigations
Authors: Schneider L.K. , Rieke W.O.
Published: April 2008

Lymphocytes obtained from cardiac blood and thoracic duct lymph of the opossum (Didelphis virginiana) were incubated in short-term culture with phytohemagglutinin. Relatively pure inocula of lymphocytes were prepared through elimination of erythrocytes and granulocytes. A critical condition for successful culture growth was found to be the use of heat-inactivated rat serum in place of autologous or isologous sera. Because of rapidly occurring bursts of DNA synthesis, cellular transformation and mitotic activity, cultures were harvested at one half the incubation time common to human blood cultures and those of other laboratory animals. Opossum lymphocytes provide excellent material for cytogenetic investigations because of this short incubation requirement and because their chromosomes are large and few in number. Particularly significant is the ease with which the sex chromosomes may be identified.