bluuebunny/crossref_metadata_2025 huggingface dataset:
XY/XXY and Sex Chromatin Positive Cell Distribution in a 60 mm Human Fetus
Authors: Klinger H.P. , Schwarzacher H.G. , Debrunner Gerda
Published: April 2008

A 60 mm crown-rump length anatomically normal male fetus is described in which approximately 7 to 19% of the somatic and extraembryonic cells are sex chromatin positive. About an equal percentage of cells grown in culture from various regions of the body were also sex chromatin positive and chromosome analysis of replicate cultures showed that a proportionate number of cells had a total of 47 chromosomes with XXY sex chromosomes. The remaining cells had a normal male chromosome complement. Single sex chromatin positive nuclei or groups of nuclei, sometimes numbering several hundred, were found in the tissues derived from all primary germ layers throughout the entire body and extraembryonic membranes. On the basis of these findings it is suggested that this mosaic condition arose at a very early stage, possibly at the third somatic division, but certainly before tissue differentiation had occurred, through a non-disjunction of a normal male cell. This study sheds some light on the mechanics of embryonic development. The value of the sex chromatin as a marker for detecting mosaic conditions involving the X chromosomes is well illustrated as is the fact that a mosaic can be overlooked when samples are taken from a limited region of the body or if only a small number of cells are studied.
Chromosomal Disturbances Observed in Human Fetal Renal Cells Transformed in vitro by Simian Virus 40 and Carried in Culture
Authors: Yerganian G. , Shein H.M. , Enders J.F.
Published: April 2008

Karyological disturbances observed during the 6th to 17th subcultures in three lines of SV40-transformed human fetal renal cells were not evident in the 1st to 3rd subcultures of uninoculated control cells. The available evidence supports the hypothesis that the observed aberrations reflect changes in the cell genome attributable to cell-virus interaction at the time of transformation. An ancillary role of environmental factors during subcultivation subsequent to transformation in the selection of certain of the observed abnormalities is suggested by the experimental findings.
DNA Replication Patterns of the Heterochromosomes in Gallus domesticus
Authors: Schmid W.
Published: April 2008

1. In short-term tissue culture, bone marrow cells of adult chicken were treated with tritiated thymidine for the last 2–4 hours prior to fixation. Autoradiographs made from these cells permit the study of the final stages of DNA replication in the chromosomes. 2. Uptake of tritiated thymidine was found in both macro- and microchromosomes. Generally, the uptake ceases earlier in the microchromosomes than it does in segments of all six pairs of macrochromosomes. In the macrochromosomes, DNA synthesis is completed according to a distinct pattern. 3. In the homogametic male sex, the two Z-chromosomes were found to replicate DNA and to cease replication at a rate and time comparable to the other macrochromosomes. There is no significant difference in labeling pattern between the two Z’s. This is a remarkable contrast to the situation found in the homogametic female sex of the mammals. 4. In the heterogametic female birds, the single Z-chromosome showed a replication pattern not different in rate and relative timing from the two Z-chromosomes of the male. 5. In all of the labeled female cells and in none of the labeled male cells, a single element of the larger microchromosomes exhibited a very heavy and comparatively late uptake of tritiated thymidine. This observation is strongly reminiscent of the replication pattern of the mammalian Y-chromosome. It appears that this late labeling microchromosome is identical with the W-chromosome first reported by Frederic (1961).
The Use of Chromogenic Reactions for the Study of Enzymic Markers in Populations of Mammalian Cells Cultured in vitro
Authors: Maio J.J. , De Carli L.
Published: April 2008

Fourteen tests based on chromogenic enzymic reactions have been performed on clonal populations of a human embryonic epithelium cell strain (EUE) in order to determine which enzyme characters may best be studied for the detection and isolation of enzyme-deficient variants. The usefulness of the enzymic reactions in the selection of genetic markers was evaluated on the basis of the following considerations: a) sensitivity of the indicator reaction; b) effect on the viability of the cells; c) presence of spontaneous enzyme deficient variants. At present, two enzymes, namely, alkaline phosphatase and glucose-6-phosphate dehydrogenase, seem to be particularly suitable for study in the selection of variants bearing specific enzymic markers, and in fact, a number of deficient cell lines have been readily isolated from strain EUE.
An Adult Triploid Chicken (Gallus domesticus) with a Left Ovotestis
Authors: Ohno S. , Kittrell W.A. , Christian L.C. , Stenius C. , Witt G.A.
Published: April 2008

Cytological studies of a fully-grown Rhode Island Red chicken (Gallus domesticus) with ambiguous sexual characteristics revealed a triploid chromosome constitution with two Zs (3A-ZZ). While this bird had the left oviduct and right rudimentary gonad of a normal hen, the left gonad was like an ovotestis with a sharply defined cortex and medulla. In the cortex were embryonic ovigerous cords containing oöcytes in first meiotic prophase; those oöcytes which had reached dictyotene and formed primordial follicles were degenerative. In the medulla were well-developed seminiferous tubules, a few of which contained sperm heads, although in most spermatocytes, meiosis had not proceeded very far. No diploid cells were found in squash preparations of spleen, bone marrow, or gonad; both somatic cells and germ cells were triploid.
Chromosome Studies in Mongoloids and Their Families
Authors: Dekaban A.S. , Bender M.A. , Economos G.E.
Published: April 2008

Studies were made of the somatic chromosome constitutions of a group of 14 mongoloids, including two who were sibs, together with the available members of their immediate families. In eight cases the classical trisomy for chromosome 21 was the only abnormality observed. The mongoloid sibs fell into this category. In the remaining six cases, however, some other abnormality was also observed in the mongoloid family. The abnormalities seen include an unusually long Y chromosome, an unusually long small acrocentric, an abnormal chromosome 18, and translocations or deletions in some portion of the karyotypes. The high frequency of abnormal chromosomes in these families suggests that these “minor” abnormalities may increase the frequency of nondisjunction of other chromosomes during meiosis, thus increasing the probability of mongoloid offspring in these families.
Chromosome Mosaicism in a Mongol Born to a Young Mother
Authors: Blank C.E. , Lord Mary , Casey M.D. , Laurance B.M.
Published: April 2008

Chromosome abnormality associated with the clinical syndrome of mongolism can usually be attributed to primary non-disjunction during gametogenesis. Nevertheless, a variety of chromosome abnormalities not attributable to primary non-disjunction during gametogenesis have been described, usually in mongols born to young mothers. The authors of this paper report a 48/46 chromosome mosaicism in a mongol born to a young mother. The cell line with 48 chromosomes has five chromosomes of the 21–22 group (Denver system) and a centric fragment. The cell line with 46 chromosomes has an extra chromosome with the morphology of the 19–20 group and only three chromosomes of the 21–22 group. It is suggested that this mosaicism resulted from concurrent non-disjunction of a number 21 and transverse division of the centromere of a second number 21 during early cleavage in a zygote, or cell line, with 47 chromosomes and trisomic for chromosome number 21.
Chromatid-Type Aberrations Induced by X Rays in Human Leukocyte Cultures
Authors: Bender M.A. , Gooch P.C.
Published: April 2008

Human peripheral leukocyte cultures 66 hours old have been irradiated with X rays and fixed 6 hours later. The cells were scored for chromosomal aberrations. The aberrations seen were mainly of the chromatid type, and included all of the expected types. The average coefficient of breakage production for four experiments was 0.0031, or virtually the same as that found earlier (Bender and Gooch, 1962a) for chromosome-type aberrations induced in the human leukocyte system.
A Family Showing Transmission of a D/D Reciprocal Translocation and a Case of Regular 21-Trisomic Down’s Syndrome
Authors: Hamerton J.L. , Giannelli F. , Carter C.O.
Published: April 2008

A family showing transmission of a D/D type translocation is reported. The chromosomes involved are probably Nos. 13 and 15 (Denver). Attempts to localize a number of marker genes in relation to the centromere of the translocated chromosome were unsuccessful. The propositus in this family was a case of regular (21-trisomy) Down’s syndrome (Mongolism). The possible association between non-disjunction and the translocation is discussed both in relation to the present family and others in the literature.
The Creeping Vole (Microtus oregoni) as a Gonosomic Mosaic. I. The OY/XY Constitution of the Male
Authors: Ohno S. , Jainchill J. , Stenius C.
Published: April 2008

Both sexes of Microtus oregoni are gonosomic mosaics; the male with the OY/XY constitution, the female the XX/XO. The diploid chromosome number of 17 originally reported by Matthey (1956, 1958) holds true only for male germ cells (OY) and female somatic cells (XO). The male, which develops from an XY-zygote with 18 chromosomes, produces two kinds of gametes; one with the Y, the other with no sex element; the X has been eliminated from the spermatogonia. Thus in this species the sperm with no sex element at all is female-determining; the XO-zygote develops into a female lacking a paternal X-chromo-some.
Comparative Cytology and Chromosome Polymorphism in African Pigmy-mice (Mus) belonging to the Groups Bufo-triton and Minutoides (Mammalia-Rodentia)
Authors: Matthey R.
Published: April 2008

1) In a previous paper published in 1963, the author showed that in a population of Mus minutoides musculoides found in Bangui, Republic of Central Africa, there were individuals with 30, 31, 32, 33 and 34 chromosomes forming a polymorphic Robertsonian system. The present study shows that M. m. minutoides (Cape Province) and M. m. bellus (Tanganika) have 36 and 30 chromosomes respectively. The subspecies names are provisional since the difference in the chromosome complements of three forms is so great that interbreeding appears to be impossible even though they cannot be distinguished according to the methods of typological taxonomy. From the cytological standpoint we have three different species, respectively designated by the letters A (M. m. musculoides), B (M. m. bellus) and C (M. m. minutoides). Group bujo-triton: Three males of M. triton (Tanganika) were analysed and again found to form a polymorphic Robertsonian system with 20, 21 and 22 chromosomes. Two females have 21 chromosomes but their chromosome constitution does not agree with those of the males. Here we are dealing with another polymorphic system whose origin implicates complicated and numerous translocations. The sex chromosomes of M. m. minutoides are of the same type as those of M. musculus. In M. m. bellus they are like those of M. m. musculoides where it is probable that a translocation of both sex chromosomes onto a pair of autosomes has occurred (Matthey, 1957, 1958, 1963). The X of M. triton is big and sub-metacentric, the Y acrocentric and relatively small. he existence of at least two polymorphic systems (M. minutoides and M. triton) and of different chromosome complements found in the forms A, B and C seems to be linked with very active processes of transformation and partially explains the difficulties met by systematists in the study of pigmy-mice.
Barr Bodies in Triploid Cells
Authors: Mittwoch Ursula , Atkin N.B. , Ellis J.R.
Published: April 2008

The presence of Barr bodies was investigated in cells of a fibroblast culture, which consisted mainly of diploid cells with two X-chromosomes and triploid cells with three X-chromosomes in approximately equal numbers. Out of a total of 1000 cells, 487 cells contained a single Barr body and 64 contained two Barr bodies. By measuring the DNA contents of interphase nuclei in arbitrary values using an integrating mícrodensitometer it could be shown that some of the nuclei containing two Barr bodies were triploid, while the rest were more highly polyploid. It is concluded that for a given number of X-chromosomes, triploid cells may contain the same number of Barr bodies as diploid cells.
Triploid-Diploid Chimerism in a Male Tortoiseshell Cat
Authors: Chu E.H.Y. , Thuline H.C. , Norby D.E.
Published: April 2008

Chromosome analysis was made on somatic cells in culture derived by necropsy from the ear and the peritoneum of a sex-chromatin positive male tortoiseshell domestic cat. A mixture of triploid (57, XXY) and normal diploid female (38 XX) cells was found in cultures of both tissue origins. The chimerism † probably existed in the cat and did not arise during in vitro cultivation. Several mechanisms for the origin of this particular chimera are suggested, including double fertilization and fusion of various types of fertilized or unfertilized meiotic products. It is postulated that the sex-linked allelic genes for the black and yellow coat color in cats follow Mendelian inheritance and that the tortoiseshell phenotype possibly is due to genetic inactivation of either X-chromosome in a heterozygous female. It is further suggested that a male tortoiseshell cat can possess an XXY sex chromosome constitution and be heterozygous for the sex-linked coat-color genes, but other types of sex chromosome anomalies and mosaicism can give rise to the same phenotype in males. The karyotype of the normal domestic cat (Felts domestica) is presented. Most, if not all, of the chromosomes can be identified. Certain similarities of karyotypes among members of Felidae are noted.
Twelve Unrelated Translocation Mongols: Cytogenetic, Genetic and Parental Age Data
Authors: Sergovich F.R. , Soltan H.C. , Carr D.H.
Published: April 2008

Cytogenetic analyses of 6 unrelated 13–15/21 translocation mongols, 6 unrelated 21–22/21 translocation mongols and almost all of their parents and sibs have been carried out. Parents carrying the translocation chromosome were found in 2 of the 13–15/21 families, but not in any of the 21–22/21 families (one father could not be tested). Mean parental ages for either type of translocation mongol were not significantly different from those for the general population. No translocation mongol had a translocation mongol relative but 4 of the 12 translocation patients had a mongol relative of the standard trisomic type. In an unselected group of 96 mongols 2 were of the translocation type (2.1 %).
Early Chromosomal Changes in SV40-Infected Human Fibroblast Cultures
Authors: Wolman S.R. , Hirschhorn K. , Todaro G.J.
Published: April 2008

The relationship between growth-rate changes and chromosomal changes during serial passage of adult human fibroblasts was examined. The phase of rapid growth in vitro is followed by a phase of progressively declining growth rate and finally, by a phase of cellular degeneration. The declining growth phase is associated with a rising level of tetraploid metaphases. In the degenerating phase, the tetraploid level increases further and aneuploid cells first appear. SV40-infection of cultured fibroblasts in the declining growth phase results in rapid and extensive chromosome alterations in the first few days following infection. Chromosome alterations in cultures 1 to 7 days after infection were examined in detail. There is a sharp increase in tetraploid metaphases due, in part, to endoreduplication. An increased frequency of breaks was seen within 2 days, and dicentric chromosomes were common by the 4th day. The normally occurring secondary constrictions became more pronounced and a member of the 6-X group, thought to be the late-replicating X chromosome, appeared to be preferentially lost. Telomeric associations involving most members of the complement were frequently encountered; evidence is presented indicating that these associations can lead to the formation of dicentric chromosomes. The telomeres of the long arm of chromosome 4 (or 5) in this cell strain were most often involved in dicentric formation. The rapid response of the several areas of relatively inert chromatin suggests an early viral effect on this material. The relationship, if any, between these early chromosome changes and the changes in the physiology of viral transformed cells remains to be elucidated.
Partial Trisomy-Deficiency Syndrome Resulting from a Reciprocal Translocation in a Large Kindred
Authors: Uchida Irene A. , Wang H.C. , Laxdal O.E. , Zaleski W.A. , Duncan B.P.
Published: April 2008

Three sibs with similar phenotypic abnormalities were found to have partial trisomy of chromosome 18 and a sizeable deficiency of one of the G chromosomes. The mother and her father as well as five other maternal relatives are carriers of a reciprocal translocation. A total of 35 individuals were tested. Viability in spite of a large deficiency may be explained by the distribution of heterochromatin and euchromatin in the acrocentric chromosome. The recovery of only one combination from adjacent segregation is probably the result of parallel orientation of a chain of four and/or early zygotic lethality. Blood grouping studies showed that the loci for Rh, MN, Duffy and Kidd are not situated on the deleted portion of the G chromosome involved.
DNA Replication Patterns of the Sex Chromosomes in Somatic Cells of the Syrian Hamster
Authors: Galton M. , Holt Sarah F.
Published: April 2008

The pattern of terminal DNA synthesis of the sex chromosomes of the Syrian hamster was studied by means of tritiated-thymidine incorporation and autoradiography. In the female, an entire X-chromosome and the long arm of the other X-chromosome underwent late replication. In the male, one of the largest submetacentric chromosomes and the long arm of the X-chromosome underwent late replication. It was presumed that this uniquely late-replicating large submetacentric chromosome was the Y-chromosome. The pattern of late replication among the autosomes was similar in both sexes and included approximately half the smallest pair of median metacentric chromosomes and the short arms of many of the larger submetacentric chromosomes. The asynchronous duplication pattern of the sex chromosomes observed in the Syrian hamster bore a striking resemblance to that previously reported in established cell lines derived from the Chinese hamster. This similarity attests to the close taxonomic relationship of these two species and is not inconsistent with the hypothesis of polyploid evolution of the Syrian hamster.
Familial Occurrence of an Abnormal D-Chromosome
Authors: Wolf U. , Baitsch H. , Künzer W. , Reinwein H.
Published: April 2008

The authors of this paper report on a satellited large acrocentric chromosome showing abnormally lengthened short arms. This chromosome was found in a mongoloid child (GLD-Trisomy), her mother, and the dizygotic twin sister of the mother, both phenotypically normal. The chromosome abnormality may have originated from a duplication of the short arms or from insertion of a piece of another chromosome between the short arms and the satellites. Since the total length of this chromosome exceeds that of the other D’s, a pericentric inversion is improbable. Normal variability and structural heterozygosity coinciding with non-disjunction are discussed.
Autosomal Trisomy in the Mouse
Authors: Cattanach B.M.
Published: April 2008

Meiotic and mitotic chromosome counts conclusively established that an adult male mouse possessed 41 chromosomes. Karyotype analyses indicated that the extra chromosome was homologous to one of the smallest autosomes – probably chromosome number 16. The animal was phenotypically normal and was only detected by the fact that it was completely sterile. Spermatogenesis was normal until after meiotic metaphase I. Subsequently, few, if any, meiotic products could be identified. The trisomy was probably the result of triethylenemelamine-induced non-disjunction in a meiotic division of the father.
Blood and Skin Chromosomal Alterations of a Clonal Type in a Leukemic Man Previously Irradiated for a Lung Carcinoma
Authors: Engel E. , Flexner J.M. , Engel-de Montmollin Mireille L. , Frank Helen E.
Published: April 2008

It is known that irradiated individuals show persistent chromosomal damages and are at greater risk of developing leukemia. In the case reported here, chronic myelogenous leukemia was diagnosed in a man three years after irradiation for surgically removed bronchogenic carcinoma. The Philadelphia chromosome was found in blood metaphases. Chromosome alterations were present in four parallel cultures of a skin biopsy taken from the site of previous irradiation. All 122 karyotyped metaphases were abnormal although their mode was diploid or near diploid or in the range of 4n for the relatively frequent polyploid cells. In this material marker chromosomes permitted the sorting of cells within five stemlines. One of the marker chromosomes in skin metaphases had the features of the Philadelphia chromosome, showing satellites and acrocentric association, although it may have arisen from any of the ten satellite acrocentric chromosomes. As a rule, studies of X-ray induced damages to blood cells in non-leukemic man have not indicated clonal perpetuation of chromosome anomalies. This case suggests that clonal evolution may have been part of regenerative processes stemming from radiation-modified survivor cells in solid tissue.
Developmental Retardation Associated with an Unbalanced 13–15/18 Translocation
Authors: Breibart S. , Mellman W.J. , Eberlein W.R. , Loftus J.
Published: April 2008

A developmentally retarded 21/2 year old male with seizures and spasticity has been found to carry only the larger product of a reciprocal translocation between the long arms of No. 18 and a 13–15 group chromosome. The absence of a smaller reciprocal of the translocation suggests that the deletions of the two involved chromosomes are the cause of the phenotypic abnormalities. The report includes dermatoglyphic analysis and blood groups, haptoglobins, Gc types and transferrins of the child and his parents.
Anatomic and Histopathologic Study of Two Cases of D1 (13–15) Trisomy
Authors: Marin-Padilla M. , Hoefnagel D. , Benirschke K.
Published: April 2008

Anatomical and histopathological study of the developmental malformation in two cases of D1(13–15) trisomy has shown that a relation appears to exist between the additional chromosome and the malformations which characterize this trisomy. The excess chromosomal material appears to be directly responsible for the duplications (kidneys, Müllerian duct derivatives, fingers and toes) and excess tissue (supernumerary lobulations of liver, pancreas, lungs and kidneys) frequently found in this trisomy. The induced excess tissue may be basically abnormal or it may provoke an imbalance between it and the surrounding normal tissue, resulting in focal morphologic abnormalities in the structure of the tissue (liver, pancreas, kidneys). In addition, there are malformations (e.g. the skeletal abnormalities of the skull and face) which are better interpreted as the result of a series of secondary anomalies which had their origin in alterations occurring early in embryonic life. The cytogenetic disturbance responsible for the trisomy is better explained as a postzygotic nondisjunction, one daughter cell receiving 45 chromosomes. The presence of the additional chromosome in the surviving cell may explain the frequent occurrence of “situs inversus solitus” in this trisomy, a phenomenon known to occur in association with monozygous twinning.
Chromosomes of Human Thyroid Tumors
Authors: Socolow E.L. , Engel E. , Mantooth Linda , Stanbury J.B.
Published: April 2008

Cytogenetic studies of one malignant and five benign human thyroid tumors grown in tissue culture are presented. In a follicular adenocarcinoma, a hyperdiploid stemline with supernumerary chromosomes in all groups was found. Abnormal chromosomes were not seen. In four of the adenomas studied, most of the cells had a normal chromosome complement. A history of prior x-irradiation to the face and neck was obtained from a fifty-four-year-old patient with a histologically benign microfollicular adenoma. Almost all of the cells had 46 chromosomes, but only a few had a normal karyo-type. The majority had a pseudodiploid chromosome complement due to either loss or acquisition of members of various groups, or the presence of abnormal chromosomes of varying size and configuration.
Enlarged Short Arm of a Small Acrocentric Chromosome in Grandfather, Mother and Child, the Latter with Down’s Syndrome
Authors: Therkelsen A.J.
Published: April 2008

An abnormal small acrocentric chromosome with enlarged short arm was found in a mother, grandfather and child, the latter with Down’s syndrome. It is probable that the chromosome originated by a mutational event in the sex cells of one of the great-grandparents as it was present in only one out of their seven children. Data are given on blood and serum types and the linkage information they provide. The nature and significance of the chromosome is discussed and it is concluded that the most likely explanation of the abnormality is heritable alteration of coiling and condensation.
A Biometric Analysis of the Chromosomes of the Marsupials – Macropus major, Macropus rufus and Potorous tridactylis
Authors: Moore Ruth
Published: April 2008

Chromosome analyses were made of three species of marsupial (Macropus major, Macropus rufus and Potorous tridactylis) using c-metaphase cells from either peripheral blood cultures or, in one case, bone marrow. The chromosomes were analysed using parameters previously suggested. In species with relatively short chromosomes, Z and Θ errors for these chromosomes are larger. It was found that the long arm of chromosome No. 1 in M. major, and both arms of chromosome No. 1 in M. rufus, contract at a different rate during metaphase than do the other autosomes in these species.
Cytogenetics of Down’s Syndrome (Mongolism) III. Frequency of Interchange Trisomics and Mutation Rate of Chromosome Interchanges
Authors: Polani P.E. , Hamerton J.L. , Giannelli F. , Carter C.O.
Published: April 2008

An attempt is made to obtain an estimate of the frequency of interchange trisomic Down’s syndrome within the general population. This estimate is used to calculate the interchange mutation rate (τ) involving chromosome 21 and resulting in the formation of interchange trisomics. Inadequacies and shortcomings of the data used, the assumptions required and the method employed are discussed. A maximum estimate of 2.71 × 10–5 (1 in 37,000) and a minimum of 2.07 × 10–5 (1 in 48,000) interchanges per chromosome 21, per gamete, per generation, resulting in the formation of interchange trisomics is obtained.
A Familial Centric Chromosome Fragment
Authors: Smith K.D. , Steinberger E. , Steinberger Anna , Perloff W.H.
Published: April 2008

An extra centric chromosome fragment was found in the karyotype of an oligospermic male and his apparently normal mother. Both karyotypes were otherwise normal and the origin of the fragment could not be determined. The possible relationship, if any, between oligospermia and the chromosomal fragment cannot be established at this time.
Enlarged Chromosome No. 1 in a Patient with Primary Amenorrhoea
Authors: Philip J. , Frydenberg O. , Sele V. , Møller Bente
Published: April 2008

The paper relates the finding of an enlarged submetacentric chromosome No. i in a patient who suffered from ACTH dependent adrenocortical hyperfunction and primary amenorrhoea. The aberrant chromosome occurred also in the patient’s father and in a sexually normal twin sister. Three similar abnormal first chromosomes have been reported in the literature but they were connected with different clinical symptoms. For this reason, as well as the lack of any observable abnormality in the patient’s father and sister, it is uncertain whether a causal relation exists between the patient’s karyotype and her clinical symptoms.
Chromosome Studies in Dogs with Congenital Cardiac Defects
Authors: Shive R.J. , Hare W.C.D. , Patterson D.F.
Published: April 2008

Chromosome analyses were made on 15 dogs with congenital cardiac defects. Abnormalities were observed in tissues from two dogs. One dog, which had other anatomical malformations in addition to the cardiac defects, had 77 chromosomes with an apparent centric fusion between two autosomes. The other dog had 79 chromosomes including a minute.
Racial Differences in the Length of the Human Y Chromosome
Authors: Cohen M.M. , Shaw Margery W. , MacCluer Jean W.
Published: April 2008

Variation in the length of the Y chromosome in a population of 100 males, derived from five different racial and ethnic sub-groups, was investigated. The Y chromosome and selected autosomes were measured in 1000 metaphase cells. Statistical analysis of the data demonstrates significant differences in mean length of the Y among some of the groups as well as among the individuals within each group. The mean length of the Japanese Y chromosome was significantly greater than that of all other groups. Among a sample of 736 circular metaphase plates, the Y chromosome was peripherally located in 241 cells.
A Chromosomal Abnormality in Phenotypically Normal Saanen Goats
Authors: Soller M. , Wysoki M. , Padeh B.
Published: April 2008

A family of Saanen goats is described in which centric fusion of two acrocentric chromosomes, giving rise to a submetacentric chromosome, has apparently occurred. The complement appeared to be genetically balanced, no phenotypic abnormalities being detected in six carriers or their offspring.
A Spontaneous Mouse Chimera Formed from Separate Fertilization of Two Meiotic Products of Oogenesis
Authors: Russell Liane B. , Woodiel Florence N.
Published: April 2008

A female mouse, having about equal proportions of yellow and black fur, arranged, roughly, in broad transverse bands, arose in a cross of +krAy un we/kr ax + un + we ♀ by kr a + un + we/kra +un+we ♂. This female was healthy, normal size, and fully fertile. Separate cell cultures derived from left pinna, right pinna, yellow-hair-bearing skin and black-hair-bearing skin yielded 40 chromosomes in almost all metaphases counted. The yellow-black female transmitted mainly three types of Linkage-Group-5 chromosomes, namely +krAy un we, kr a + un + we, and kr ax+un +we, as well as certain informative crossover products. From these results it was possible to rule out several origins that might have been postulated on the basis of phenotype and parentage alone. It is concluded that the female was a 2n/2n chimera of genotypes +krAy un we/kra +un +we and kr a× +un +we/kr a +un +we, these two genotypes being present in the ratio of about 1:1 in the skin and 3:1 in germinal tissue. Such a chimera could come about through: (1) participation of both secondary oocytes (in lieu of first-polar-body abstriction), each being separately fertilized by an X-bearing sperm; or (2) participation of both products of the second meiotic division (in lieu of second-polar-body abstriction), each being separately fertilized by an X-bearing sperm, following a crossover proximal to the most proximal of the four marked loci; or (3) fusion of two originally separate fertilized eggs or early embryos of the proper genotypes. Close parallelisms with two recently described human cases are discussed.
Comparative Study of the Karyotypes of Several Species in Carnivora Including the Giant Panda (Ailuropoda melanoleuca)
Authors: Newnham Rosemary E. , Davidson W.M.
Published: April 2008

The chromosome morphology and the sex chromatin pattern have been investigated in Ailuropoda melanoleuca (giant panda) and a number of related animals. The following chromosome numbers have been determined: Ailuropoda melanoleuca, 42; Ursus americanus, 74; Selenarctos thibetanus, 74; Tremarctos ornatus, ?54; Canis familiaris, 78; and Chrysocyon brachyurus, 76. It is suggested on cytological grounds that there may be a close relationship between U. americanus, U. middendorfi, Thalarctos maritimus and S. thibetanus, but this does not include A. melanoleuca or T. ornatus. Nevertheless in taxonomy the morphology of the chromosomes, as known at present, must only be regarded as one of many differentiating factors. Sex chromatin has been seen in the female animals investigated but not in the male. The absence of the enzyme, alkaline phosphatase, from the neutrophils of S. thibetanus, and A. melanoleuca, but not C. brachyurus, is an interesting observation.
Chromosomes of Three Elephants, Two Asian (Elephas maximus) and One African (Loxodonta africana)
Authors: Hungerford D.A. , Sharat Chandra H. , Snyder R.L. , Ulmer, Jr. F.A.
Published: April 2008

Cultured somatic cells of three elephants, male and female Asian (Elephas maximus) and female African (Loxodonta africana), had 56 chromosomes. Karyotypes of the Asian specimens were morphologically identical, except for the sex chromosomes, and that of the African specimen closely similar. Identification of the African X was made by inference.
Chromosomal Evolution in the Genus Peromyscus (Cricetidae, Rodentia)
Authors: Hsu T.C. , Arrighi Frances E
Published: April 2008

The diploid number of species and subspecies in genus Peromyscus is 48. The number of total chromosome arms (fundamental number), however, varies from 56 to 96. Apparently the changes were accomplished by reciprocal translocations and pericentric inversions, but not by the Robertsonian process.
An Air-Drying Method for Chromosome Preparations from Mouse Eggs
Authors: Tarkowski A.K.
Published: April 2008

The eggs, after being washed out from the genital tract, are put into hypotonic (1%) sodium citrate and left to stand at room temperature for 5–15 minutes. The duration of treatment is not very critical, but later stages, especially blastocysts, need longer treatment. A microdrop of this solution together with the eggs is placed on a grease-free slide. A few drops of acetic alcohol (3 parts of absolute ethyl alcohol, 1 part of glacial acetic acid) are immediately expelled from another pipette, whose tip is brought just over the microdrop containing eggs. The optimal number of drops of fixative has been found to be three in the case of eggs from the one cell to eight cell stage and five or even more in the case of blastocysts. These indications were calculated for drops measuring approximately 0.02 ml in volume. Air-dried preparations are stained in lactic-acetic-orcein or in 2% aqueous solution of toluidine blue. The method can be applied to all stages from diakinesis of the first meiotic division to blastocyst. It enables one to obtain excellent scattering of nuclei and metaphase plates and good spreading of chromosomes. The remnants of cytoplasm are negligible.
Timing of Sex Chromosome Replication in Somatic and Germ-Line Cells of the Mouse and the Rat
Authors: Tiepolo L. , Fraccaro M. , Hultén Maj , Lindsten J. , Mannini Anna , Ming Pen-Ming L.
Published: April 2008

Timing differences of the G2 periods were found among bone marrow cells labelled with 3H-thymidine in vivo, cultured kidney cells labelled in vitro and spermatogonia labelled in vivo, within the same species and also within single individuals. Differences in the timing of sex chromosome replication patterns were found among the same types of cells. The Y chromosome was extremely late-replicating in spermatogonial mitoses and also asynchronous in cultured kidney cells after four hours of contact with tritiated thymidine. Identification of differences in replication of the sex chromosomes was difficult in the bone marrow of both species; when labelled in vivo, the G2 period of these cells is on the average shorter than that of the other cell types. A morphological and autoradiographic study of mouse interphase nuclei of cultured cells did not reveal a direct relationship between appearance of multiple heteropycnotic masses in both sexes and the patterns of chromosome replication. It was found that one category of nuclei has a single sex chromatin body only in the female. The rat female nuclei have a clear, single sex chromatin.
Evidence of the Freemartin Condition in the Goat
Authors: Ilbery P.L.T. , Williams D.
Published: April 2008

Cytogenetic examination of a genetically polled intersex goat revealed a state of apparent XX/XY haemopoietic chimaerism. As this goat was born with a male litter mate, it is considered to be a freemartin. The possibility that genetic goat intersexes are also freemartins is suggested.
Chronology and pattern of human chromosome replication
Authors: Takagi N. , Sandberg A.A.
Published: April 2008

The pattern of initiation of DNA replication in normal male and female human cells was studied by a modified method of Mukherjee and Sinha (1965). One of the X chromosomes of female and the Y chromosome of male cells were found to begin DNA replication definitely later than other chromosomes. The possible cause of the discrepancy among reported studies was discussed.
Chromosomes and the classification of the snakes of the family Boidae
Authors: Singh L. , Sharma T. , Ray-Chaudhuri S.P.
Published: April 2008

The chromosomes of the Indian rock python, Python molurus (sub-family Pythoninae), and the sand boa, Eryx johni johni (Boinae), were investigated and compared with those of Boa constrictor (Boinae). A striking similarity of the chromosomes of Boa and Python was observed, but the karyotype of the Eryx was found to be different from that of the other two species. This investigation clearly supports the validity of the doubt expressed by some taxonomists regarding a close phylogenetic relationship between Boa and Eryx.
Meiosis in the human female
Authors: Yuncken Catherine
Published: April 2008

Techniques are now available for the study of meiosis in the human female through the short term culture of oocytes from ovaries. One cell, in which 23 bivalents could be distinguished, shows interstitial chiasmata in the bivalents, in which all four strands can be distinguished. The small bivalents appear to terminalise first. The chiasma count was consistent with the number in the male.
Replication of human chromosomes in primary cultures of embryonic fibroblasts
Authors: Slezinger S.I. , Prokofieva-Belgovskaya Alexandra A.
Published: April 2008

Chromosome replication at the beginning and termination of the S period in a primary culture of embryonic human fibroblasts has been studied through the use of 3H-thymidine labeling and autoradiography. In the analysis the observed numbers of silver grains above chromosomes were compared with those expected on the assumption of uniform labeling throughout the whole chromosome complement. The S period began almost simultaneously in all chromosomes but No. 1 (in which synthesis began very early) and the Y (in which it began late). The chromosomes terminate their replication asynchronously; Nos. 2, 3, 4–5 and 19–20 terminate DNA synthesis early, while Nos. 1, 16, 21–22 and the Y replicate late. The results obtained have been compared with published data on DNA replication in cultured peripheral blood leucocytes. The differences found in chromosome replication (especially in that of Nos. 1 and 2) may be due to differences in the function of these chromosomes in the two cell types.
XX/XY chimerism in a bovine true hermaphrodite: an insight into the understanding of freemartinism
Authors: Dunn H.O. , Kenney R.M. , Lein D.H.
Published: April 2008

The anatomic, histologic and cytogenetic findings on a bovine true hermaphrodite are discussed. The XX/XY chimerism in various tissues, including the kidney and testicular tissue of the ovotestis, combined with the presence of a uterus, cervix, vagina, seminal vesicles, penis and ovary provide evidence for dispermic fertilization involving two ova or an ovum and its nonextruded polar body. Circumstantial evidence regarding the mechanism of freemartinism is discussed.
Chromosomes of the sterile hybrid duck
Authors: Mott C.L. , Lockhart Lillian H. , Rigdon R.H.
Published: April 2008

The hybrid duck resulting from the mating of a Muscovy male and a White Pekin female is sterile. Utilizing a technique for the culture of blood cells, chromosome preparations were made of the parental and hybrid ducks. Morphological differences were found to exist between the first and fourth pairs of chromosomes of the Muscovy and the White Pekin. The first pair of chromosomes has a long-to-short arm ratio of 2:1 in the Muscovy and 1.6:1 in the White Pekin. The sex chromosome pattern of both species was found to be ZZ/ZW, rather than ZZ/ZO, with the Z and the W occupying relatively the same positions in the different ducks. The fourth pair of chromosomes, representing the sex chromosomes of the male duck, possesses short arms in the White Pekin but not in the Muscovy. This difference in morphology is probably significant with reference to the sterility of these hybrids. Studies of the gonads have indicated that gametogenesis does not proceed past the first stage in meiosis. Synapsis of homologous chromosomes from the two parent species evidently does not occur because of differences in morphology.
Chromosomes of Peromyscus (Rodentia, Cricetidae)
Authors: Hsu T.C. , Arrighi Frances E
Published: April 2008

The somatic metaphase chromosome constitutions of 20 Peromjscus species (188 specimens) were described and compared. Peromyscus (Ochrotomys) nuttalli, which has been considered by many mammalogists as a member of a separate genus, Ochroiomys, has a diploid number of 52. All other 19 species possess a diploid number of 48. The lowest number of total chromosome arms is 56 (P. crinitus and P. boylei) and the highest is 96 (P. eremicus and P. collatus). Since the number of centromeres remains the same, Robertsonian fusion is not found in the genus Peromyscus. The X chromosome, with one doubtful exception, is always a large, biarmed element, but the Y chromosome is extremely variable in size as well as in centromeric position. Intraspecific polymorphism is extensive in many species, and in some cases, e.g., P. truei, cytological data strongly suggest that there may be more than one species under one name. The survey indicates that it may be extremely profitable to use Peromyscus cytology to analyze species relationships, population structure, population dynamics and other evolutionary processes. Phylogenetic relationships among the species thus far analyzed are discussed.
Comparative study of the association of human acrocentric chromosomes in male and female mitoses
Authors: Galperin Helene
Published: April 2008

This paper deals with a statistical study of the spatial relationships between the acrocentric chromosomes in men and in women as can be inferred from the analysis of metaphase figures. This analysis confirms the hypothesis that the acrocentric chromosomes are not randomly situated and shows as a new fact that this effect is considerably more striking in women than in men. This might account for a part of the prominent role attributed to the mother in many cases of mongolism.
An XYY sex-chromosome constitution in the mouse
Authors: Cattanach B.M. , Pollard C.E.
Published: April 2008

A phenotypically normal male mouse, investigated because it was sterile, was found to possess 41 chromosomes. A karyotypic analysis indicated the extra element was one of the smallest chromosomes, almost certainly the Y. X-Y bivalents, Y-Y bivalents and XYY univalents were seen in meiotic metaphase I cells, and it was therefore concluded that the extra chromosome was indeed the Y. Spermatogenesis tended to break down after meiosis I, but a few spermatids and sperm were observed.
Chromosomal nondisjunction: the action of Colcemid on Chinese hamster cells in vitro
Authors: Cox D.M. , Puck T.T.
Published: April 2008

Quantitative study has been carried out of the conditions under which exposure of Chinese hamster cells to Colcemid produces polyploidy, chromosomal aneuploidy and cell killing. Single cell survival curves indicate that survival decreases with increasing exposure time and drug concentration. However, for exposure periods of 24 to 48 hours and drug concentrations in the neighborhood of 0.05 to 0.9 µg/ml, a plateau is reached at 20 to 50% survival. No appreciable change in chromosome counts occurs at or below 0.01 µg/ml. At 0.015 µg/ml, counts indicative of nondisjunction appear and increase, reaching a maximum at 0.02 µg/ml. From 0.03 to 0.07 µg/ml, approximately 80% of the cells are tetraploidized. A variety of clones with additional chromosomes can be obtained which may be useful for genetic-biochemical studies. Chromosome losses are also produced, but under the conditions employed here, these were generally inviable. The system appears to lend itself to screening of various agents for their ability to produce changes in chromosome number in mammalian cells in vitro.
Chromosome aberrations and culture time
Authors: Honda T. , Kamada N. , Bloom A.D.
Published: April 2008

Leukocytes from 17 A-bomb-exposed survivors and 10 control persons of the same age group were cultured for two and three days. Among the controls, aberrations other than single or isochromatid lesions were seen in 0.6 % of cells at two days of culture and in 0.8% of cells at three days of culture. Among the exposed, 7.0% of cells cultured for two days had these aberrations, which were seen in 8.7% of cells cultured for three days. Six cytogenetically aberrant clones were found in 5 of the 17 exposed survivors. Four of these were detectable on the basis of the two-day culture results alone. Since our previous studies of 171 heavily exposed survivors, using the 66 to 70 h culture time, had enabled us to detect only four clone-formers, it appears that the shorter culture time enhances clone detection.
Human chromosome identification and the pattern of DNA replication in fibroblasts from an XXY male
Authors: Ockey C.H.
Published: April 2008

A statistical study of early and late DNA synthesis in segments of chromosomes from XXY fibroblasts was performed in order to establish the accuracy of karyotyping on a morphological basis in relation to the labelling patterns over the chromosomes. Cells were labelled with 3H-thymidine after incomplete synchronisation with a DNA inhibitor (5-fluorodeoxyuridine). The late-S pattern was, in general, found to complement the early-S pattern, and 71 % of the chromosome segments were significantly either early or late labelling. The larger late-labelling segments, typified by those in chromosome 4 and the late-labelling X, continue synthesis after the smaller ones (Nos. 21 and 22 and the Y) have more or less reached completion. In 40 cells from late- or early-labelled samples, where chromosomes were first karyotyped without reference to labelling behaviour, the following chromosomes showed significantly distinct patterns and could be distinguished from each other or from other chromosomes in their Denver groups: Nos. 4 and 5, the early-labelling X, Nos. 9, 11, 13, 17 and 18 and the Y. In a sample of 20 cells labelled at an early or penultimate stage of late-S, other chromosomes, including Nos. 14, 15, 21 and 22, showed unique labelling patterns. At no stage could chromosomes 8 and 10 or 19 and 20 be distinguished from one another in their respective groups on the basis of labelling pattern. The study indicates that even with errors arising from misclassification of chromosomes and the inherent within- and between-cell variability in labelling, significant differences in labelling behaviour of chromosomes can be demonstrated in a partially synchronised population labelled at the correct stage of DNA synthesis.