bluuebunny/crossref_metadata_2025 huggingface dataset:
Status of prezygotic chromosome lesions in relation to cancer
Authors: Nichols W.W.
Published: May 2008

There are currently three recognized prezygotic chromosome defects that are associated with specific cancers. These are a deletion of band 13ql4 with retinoblastoma, a deletion of band llpl3 with Wilms’ tumor associated with aniridia, and a reciprocal translocation of chromosomes 3 and 8 with clear cell cancer of the kidney. The two deletions have been assumed to be variants of the hereditary subgroup of tumors. There are many obvious similarities between retinoblastoma associated with deletion of 13ql3 and Wilms’-aniridia associated with deletion of llpl3, but there are also significant disparities. Each time a deletion of 13ql4 has been found it is associated with a retinoblastoma, while deletions of llpl3 have been associated with nephroblastoma in only 4 of 11 cases. When bilateral disease occurs it is usually seen simultaneously in both eyes with retinoblastoma, but with bilateral nephroblastoma the appearance of the first and second tumors is separated by a year or more. These disparities indicated the possibility that more than one etiologic mechanism may operate even within this group of specific chromosomal mutations associated with specific tumors.
A perspective on mechanisms of chromosomal mutations in relation to chromosome-stability-deficient mutants of Drosophila
Authors: Kondo S.
Published: May 2008

A working hypothesis that eukaryote chromosomal mutations result from specific misrecombination is proposed in relation to X-ray-induced mutations in the mouse. Unique features of chromosome-stability-deficient mutations and of tumor mutations in Drosophila are reviewed; these mutations could serve as very good models for elucidating the mechanisms of chromosome-aberration-related diseases in humans.
Identification of MIC5, a human X-linked gene controlling expression of a cell surface antigen: definition by a monoclonal antibody raised against a human x mouse somatic cell hybrid
Authors: Hope R.M. , Goodfellow P.N. , Solomon E. , Bodmer W.F.
Published: May 2008

We have combined the recently developed monoclonal antibody techniques and an experimental protocol for the definition of chromosome-specific cell surface antigens in order to produce a monoclonal antibody, Rl, which recognizes an X-linked human cell surface antigen.
Mid-pachytene chromomere maps of human autosomes
Authors: Jhanwar S.C. , Burns J.P. , Alonso M.L. , Hew W. , Chaganti R.S.K.
Published: May 2008

Using a method of chromosome preparation which yielded pachytene spermatocytes with exceptionally well spread bivalents, we undertook detailed chromomere analysis of each of the 22 autosomal bivalents stained with orcein or quinacrine. A maximum of 442 chromomeres were recognized and mapped at mid-pachytene. The chromomere maps of pachytene chromosomes presented here corresponded well with the high resolution banding maps of somatic chromosomes at the 850 band stage described in the International System for Human Cytogenetic Nomenclature (ISCN, 1981). Our observations of other features of the pachytene chromosomes, such as the parameres, also agree well with previous reports.
Aging and sister chromatid exchange
Authors: Schneider E.L. , Bickings C.K. , Sternberg H.
Published: May 2008

The frequency of background or spontaneous sister chromatid exchanges (SCE) was estimated in young and old rat and mouse bone marrow cell populations by exposing these cells to increasing concentrations of bromodeoxyuridine (BrdU). At the lowest levels of BrdU where SCE could be accurately assessed, there was no significant difference in background SCE between young and old cell populations. Extrapolation to zero BrdU concentration yielded SCE frequencies of approximately 1.0 SCE/cell/cell cycle in both mouse and rat cells.
Chromosome localization of the genes for isocitrate dehydrogenase-1, isocitrate dehydrogenase-2, glutathione reductase, and phosphoglycerate kinase-1 in the American mink (Mustela vison)
Authors: Rubtsov N.B. , Radjabli S.I. , Gradov A.A. , Serov O.L.
Published: May 2008

Twenty-eight hybrid clones with different mink chromosomes were derived from the fusion of Chinese hamster and American mink (Mustela vison) cells. This set of clones made it possible to assign the mink genes for isocitrate dehydrogenase-1 (soluble) to chromosome 4, for isocitrate dehydrogenase-2 (mitochondrial) to chromosome 10, for glutathione reductase to chromosome 6, and for phosphoglycerate kinase-1 to the X chromosome.
G bands of prematurely condensed mouse diplotene bivalents
Authors: Drwinga H.L. , Pathak S.
Published: May 2008

G-banding was induced along prematurely condensed mouse diplotene bivalents. The banding patterns of the diplotene chromosomes demonstrated a good correspondence with patterns of banded mouse metaphase chromosomes. The differentiation present along the mitotic chromosomes appears to be conserved in the diplotene cell.
Comparative gene mapping: murine lambda light chain genes are located in region cen→B5 of mouse chromosome 16 not homolous to human chromosome 21
Authors: Francke U. , de Martinville B. , D’Eustachio P. , Ruddle F.H.
Published: May 2008

We have mapped the genes for murine immunoglobulin lambda light chains to the region of chromosome 16 proximal to band B5 by hybridizing a cDNA probe for X light chains to the DNA of a series of hybrid clones made between mouse fibroblasts carrying Searle’s translocation, T(X;16)16H, and Chinese hamster cells. Based on homology, we predict that the human Igl genes (IGL) will map to the proximal two-thirds of HSA 22.
Karyotype stability in marine mammals
Authors: Árnason Ú.
Published: May 2008

A considerable amount of information is now available on the karyology of the marine mammals, Pinnipedia and Cetacea. This information emanates both from banded and unhanded karyotypes. A majority of the pinnipeds has now been investigated karyologically, and representatives of all extant cetacean families have also been studied. The karyotype stability among the marine mammals has been stressed earlier, and the present discussion emphasizes this point further.
Homozygous deficiency: Syrian hamsters with only 42 chromosomes
Authors: Breckon G. , Savage J.R.K.
Published: May 2008

By crossing individuals of a line of Syrian hamsters (1SH), 2n = 43, which lack one derivative chromosome (der 11) of a reciprocal translocation, T(l 1;20), two homozygous deficient males were obtained. These animals have only 42 chromosomes and completely lack the centromere and short arm of chromosome 11 and most of the long arm of chromosome 20. Phenotypically and anatomically these animals are apparently normal. Meiosis in both animals was regular with 21 bivalents, and mature sperm were produced. One of the animals sired two litters when mated to normal females. Detailed cytogenetic studies gave no evidence of mosaicism, and the kinetic behaviour of blood and skin cells in short-term culture was identical to control (2n = 44) cells. The detailed kinetics of DNA synthesis of fibroblasts in vitro did not differ from those of normal cells. The missing material, which constitutes about 2.5% of the total chromosome length, synthesizes DNA late, replicating bands being absent until the last sub-phase (Sk5) of the hamster S phase.
High resolution G-banding patterns of Syrian hamster chromosomes
Authors: Li S. , Pathak S. , Hsu T.C.
Published: May 2008

The late prophase, prometaphase, early metaphase, and metaphase chromosomes of Syrian hamster embryo fibroblast cells were G-banded using a technique combining actinomycin D pretreatment and Wright/Giemsa staining. Late prophase chromosomes have approximately twice as many bands as metaphase chromosomes, whereas prometaphase and early metaphase chromosomes have intermediate numbers of bands. An idiogram for metaphase and late prophase chromosomes is presented, and a nomenclatural system for identifying individual bands of Syrian hamster chromosomes is proposed.
Chromosomal evolution in allopatric populations of the Odontophrynus occidentalis group (Amphibia, Anura) from western Argentina
Authors: Ruiz I.R.G. , Ceis J.M. , Beçak W.
Published: May 2008

A karyological study of some populations of the Odontophrynus occidentalis group (2n = 22) from Argentina is reported. Ammoniacal silver (Ag-AS) and alkaline Giemsa (CBG) staining have been performed on specimens from La Rioja, Mendoza, Malargue, Tamelen, Tapiluque, Valcheta, and Meseta de Somuncura. All populations showed active ribosomal cistrons (NORs) on chromosome 11. Some metaphases of three specimens from Mendoza and five from La Rioja also showed bands on 9. Centromeric and telomeric C-bands were common to all populations, and a block of heterochromatin on both sides of the centromere of 2 was remarkable in all but the La Rioja populations. The specimens from La Rioja showed a similar block of heterochromatin on the short arm of 1. Taxonomic studies of several specimens from these localities revealed differences in larval development, glandular pattern, the size of specimens, etc. As a whole, biological as well as karyological features suggest that the isolated population at La Rioja is a separate entity, at the species level, as described elsewhere.
The chromosomes of the bongo, Taurotragus (Boocerus) eurycerus
Authors: Benirschke K. , Kumamoto A.T. , Esra G.N. , Crocker K.B.
Published: May 2008

Chromosome studies on 14 bongos, Taurotragus (Boocerus) eurycerus, disclosed that males have 33 and females 34 chromosomes. The acrocentric Y chromosome is fused to the acrocentric autosome 13. Two X-chromosomal types exist, one a large acrocentric that is identical to that of other tragelaphines, and the other a submetacentric. The latter is produced by the addition of heterochromatin as a new short arm and not, as previously believed, by pericentric inversion. The inheritance of the different X-chromosome morphotypes is followed in one pedigree. Homozygous females for both morphotypes exist and appear to be normal.
Observations on the argentophilic properties of mammalian spermatids
Authors: Elder F.F.B. , Hsu T.C.
Published: May 2008

We have used aqueous silver nitrate to stain preparations of formalin-fixed meiotic cells. In doing so we have “rediscovered” a number of spermatid organelles, such as nuclear rings, acrosomal cap rings, centriolar adjuncts, and developing annuli, apparently not seen in numerous other recent studies of silver-stained meiotic cells. The availability of these structures for light microscopy coupled with the ease of preparation of the samples should facilitate studies on spermatid development, cytochemistry, and differentiation.
Robertsonian karyotype variation in wild house mice from Rhaeto-Lombardia
Authors: Gropp A. , Winking H. , Redi C. , Capanna E. , Britton-Davidian J. , Noack G.
Published: May 2008

The European longtailed house mouse (M. m. brevirostris and domesticus) in the Rhaetian Alps and Lombardia presents a complex system of Robertsonian (Rb) variation and karyotype diversity, several adjoining populations homozygous for multiple Rb metacentric chromosomes, sites of coexistence of different Rb types, and zones of hybridization with non-Rb populations. The original “tobacco mouse” is just one of many local Rb variants, such as those from other Alpine areas (e.g., Orobian Alps) or from Central Lombardia, where a relatively large region within which the population is homogeneous for multi-Rb metacentrics is found. The present study is based strictly on material in which the chromosome arms were identified by G-banding, so that karyotypes within the areas under investigation could be compared. Altogether Ill mice were studied.
Organ cultures of mammalian testes
Authors: Koulischer L. , Hustin J. , Demoulin A. , Franchimont P. , Debry J.M.
Published: May 2008

Meiotic chromosomes of adult mice testes cultured in vitro have been studied. All meiotic stages are present and normal until the 8th day; suitable figures for chromosome studies may be obtained with routine cytogenetic methods. During the 9th and 10th day in vitro, the number of cells in meiotic progress falls abruptly. By the 14th day, only a few pachytene stages are still observed. This breakdown of meiosis, linked with the disappearance of the germ cell line, is not due to chromosome anomalies that could have arisen in the new environment. Labeling with tritiated thymidine suggests that spermatogonia do not enter meiotic division in vitro. Chromosomes observed with this technique belong to cells already involved in meiotic processes at time of the initiation of the culture.
Single-copy DNA and vertebrate phylogeny
Authors: Morescalchi A. , Olmo E.
Published: May 2008

A study of genome sizes and repetitive and nonrepetitive nucleotide fractions in some reptiles, selachians, and amphibians showed that not one of these organisms possesses the percentage of single-copy DNA presumed to be typical of animals (70%). The data on the samples investigated, when compared with those existing in literature on other vertebrates, indicate certain general characteristics of the genome of this important animal group, which in this work are interpreted in terms of their adaptive functions. Each of the main systematic categories of the subphylum (classes or orders) has peculiar features as to the genome size and percentage of unique or repetitive DNA fractions. Among anamniotes (i.e., teleosts, selachians, and amphibians) the percentages of the single-copy DNA are lower than among amniotes (i.e., reptiles, birds, and mammals) and inversely proportional to genome sizes, which does not occur in amniotes. Also on the basis of some karyologic evidence, the hypothesis is put forth that such differences may reflect the adoption, in the course of evolution of the amniotes, of new genetic strategies which have deeply influenced the genomic molecular structure.
The common ancestry of genes and spacers in the euchromatic region: omnis ordinis hereditarium a ordinis priscum minutum
Authors: Ohno S.
Published: May 2008

Genes in the euchromatic region of mammalian chromosomes can be compared to oases in a barren stretch of desert. The average distance between neighboring genes is estimated to be 35 kbp (kilo-base pairs). This great preponderance of intergenic spacers in the euchromatic region is due mostly to the extreme inefficacy of the mechanism of gene duplication as a means of creating new genes with altered active sites. For every redundant copy of the pre-existent gene that emerged triumphant as a new gene, hundreds of other copies must have degenerated to join the rank of junk DNA. The average functional half-life of redundant gene copies has been estimated as 50 million years. Not surprisingly, each still functioning gene of mammals is, as a rule, flanked by copies in varying degrees of degeneracy, so-called silent pseudogenes. I propose that the entire euchromatic region, genes and spacers included, evolved from a few primordial sequences. The primordial sequence was (AGCTG)(AGCTG)(AGCTG) (GGGTG) in the case of the regions housing the immunoglobulin family of genes. Deep in the interior of each long intergenic spacer dwells a core made of exact replicas of this primordial sequence, and each core is flanked by its degenerate subfamilies of repeats. Between the nearest core and either end, 2 to 3 kbp away, of each long spacer, subfamilies of repeats are arranged in a descending order of relatedness to the primordial sequence as well as in their intra-subfamilial sequence fidelity among copies. Consequently, sequence repetitiousness becomes cryptic in the terminal region of the spacer immediately upstream or downstream of a gene. Nevertheless, coding sequences of the gene are contiguous with adjacent regions of the spacer in every sense, for the coding sequence also embodies the cryptic repetitiousness within it. The contiguity is made evident by the indiscriminate occurrence of descendants of the same building block in the coding sequence and adjacent spacers. It is the choice of its particular primordial building block ultimately derived from (AGCTG)(AGCTG)(AGCTG)(GGGTG) which gives the specific characteristics to each family of genes. For example, the ancestral gene for immunoglobulin light chain constant regions of both x and X classes apparently arose from about 20 tandem repeats of the 36-base-long primordial building block: CCA-TCT-GTC-GTG-AAG-CTG-CTA-AAG-AAC-ATC-AGT-CGC.
Heterochromatin, synaptonemal complex, and NOR activity in the somatic and germ cells of a male domestic dog, Canis familiaris(Mammalia, Canidae)
Authors: Pathak S. , Van Tuinen P. , Merry D.E.
Published: May 2008

C-banding and silver staining of the somatic and germ cells of the male domestic dog, Canis familiaris, have shown that: (1) the amount of C-banding is small compared to most other mammalian species, (2) three pairs of autosomes have nucleolus organizer regions (NORs) at the terminal ends of their long arms, whereas the Y chromosome has an NOR on the terminal end of the short arm, (3) the organization of the synaptonemal complex (SC) is similar to that of other mammalian species, (4) a distinct SC is formed between the long arm of the Y chromosome and probably the short arm of the X chromosome, and (5) the differential axes of both sex chromosomes do not demonstrate fusiform thickenings nor do they stain darkly with silver as do the XY bivalents in many other mammalian species.
Comparative analysis of karyotypes in European shrew species
Authors: Schmid M. , Schempp W. , Olert J.
Published: May 2008

The chromosomes of the two closely related species Sorex araneus and S. gemellus were investigated by various methods for the determination of constitutive heterochromatin (C-band techniques, treatment of cell cultures with AT- and GC-base-pair-specific compounds, and analysis of late-replication patterns). With the exception of the Yi sex chromosomes, no distinct heterochromatic regions like those in other mammals were demonstrated. Although use of a modified C-band technique produced moderately darkly stained bands, these did not have a definite heterochromatic character. Spontaneous sister chromatid exchanges (SCE’s) occurred significantly more frequently in the Yi chromosomes than in other chromosomes. Analysis of intrachromosomal frequencies of SCE’s showed no significant deviations from a uniform random distribution.
A comparison of the karyotype, constitutive heterochromatin, and nucleolar organizer regions of the new tetraploid species Xenopus epitropicalis Fischberg and Picard with those of Xenopus tropicalis Gray (Anura, Pipidae)
Authors: Tymowska J. , Fischberg M.
Published: May 2008

A cytological analysis of the recently discovered tetraploid species Xenopus epitropicalis was carried out, using, in addition to the classical orcein method, silver staining and alkaline Giemsa banding techniques. The chromosome number of X. epitropicalis was found to be 40. The chromosomes can be grouped in to sets of four similar chromosomes (quartets), resembling the karyotype of X. tropicalis (2n = 20). However, C-band patterns revealed heterogeneity within the quartets, dividing each of them into two pairs of homologous chromosomes (“duets”). Moreover, there are differences in the position and distribution of constitutive heterochromatin between the karyotypes of X. epitropicalis and X. tropicalis. The secondary constrictions stained by silver and representing the nucleolar organizer regions (NOR’s) appear in both species on chromosome pair 5. During meiosis, usually only bivalents appear in X. epitropicalis. The question of whether this species is of autopolyploid or allopolyploid origin cannot be answered with certainty; however, it seems to have a common ancestor with X. tropicalis.
Cytogenetics of the parthenogenetic grasshopper Warramaba virgo and its bisexual relatives
Authors: White M.J.D. , Contreras N.
Published: May 2008

Eleven cytological clones of the parthenogenetic grasshopper Warramaba virgo are defined in this paper on the basis of their karyotypes and the C-banding patterns of their chromosomes. These clones are additional to the 16 clones previously described. Seven of the new clones have the standard karyotype and differ only in minor features of the C-bands, the result of amplification or diminution of heterochromatic segments. The remaining 4 clones carry translocations. Of the total of 27 clones of W. virgo now known, 9 carry translocations or fusions. The X + A chromosome is involved in five of these rearrangements and the li69 chromosome in four, suggesting a marked nonrandomness with regard to involvement in rearrangements. All the clones with translocations or fusions are known from single localities, suggesting that they are short-lived and do not spread far from their point of origin. A clone that apparently carries a paracentric inversion in one chromosome is more widespread. Clonal diversity in W. virgo seems to be maximal in the Kalgoorlie region of Western Australia, where W. virgo is believed to have arisen, on two separate occasions, by hybridization between two bisexual species. A classification of the clones on the basis of their C-banding patterns is tentatively proposed.
The interrelationships of chromosome banding patterns in canids, mustelids, hyena, and felids
Authors: Wurster-Hill D.H. , Centerwall W.R.
Published: May 2008

The G-banding patterns of six canids, four mustelids, one hyena, and 12 felids have been studied, and data from the study of 30 felids are summarized. The canids are karyotypically very similar to one another, but minor differences have tentatively been identified. The mustelids show the greatest karyotypic diversity of all the carnivore families so far studied. They do display, however, considerable G-band conservatism, as is common throughout the Order, and appear karyotypically more closely related to the Feloidea than to the Canoidea. The hyena shares many autosomes with the felids, showing a close relationship to that family. The felids are for the first time divisible into small groups or individually identifiable on the basis of 16 different karyotypic patterns.
Cytogenetic and DNA analyses of equine abortion
Authors: Haynes S.E. , Reisner A.H.
Published: May 2008

Although no major structural or numerical abnormalities were found in the karyotypes of 12 aborted equine fetuses, two unrelated abortuses each carried a large polymorphism for the amount of heterochromatin in chromosome 1. In both karyotypes this chromosome was shown to be larger than its homolog. To determine the nature of the extra DNA in these chromosomes, equine DNA was isolated and characterized by buoyant density analysis. Equine mainband DNA had a buoyant density in neutral CsCl of 1.699 g/cm3, while the highly repetitive (dG + dC)-rich fraction had a buoyant density of 1.715 g/cm3. A radioactive RNA probe complementary to the purified satellite fraction was used for in situ hybridization to chromosomal spreads containing the enlarged chromosome 1. The results indicated that an increase in highly repetitive (dG+dC)-rich DNA was responsible for the increase in the size of the abnormal No. 1 chromosomes. While two of the 12 aborted fetuses exhibited marked heterochromatic dimorphisms, none of the karyotypes obtained from individuals with no family history of abortion exhibited such obvious polymorphisms.
Suppression of transformation and tumorigenicity in interspecies hybrids of human SV40-transformed and mouse 3T3 cell lines
Authors: Howell N.
Published: May 2008

Somatic cell hybrids, formed by fusion of human SV40-transformed fibroblast lines and mouse 3T3 cells, were isolated and analysed for expression of transformation phenotypes and tumorigenic potential in immunodeficient nude mice. Both tumorigenic and nontumorigenic SV40-transformants were used for these experiments. Regardless of whether or not the parental human transformed parent line was tumorigenic, the hybrid progeny—with rare exception—did not form tumors. The possibility that human SV40-transformed lines and the derived hybrid progeny were immunologically rejected in nude mice was unlikely since fusion of these human lines to a tumorigenic 3T3 variant produced hybrids which were highly tumorigenic. In addition, in these hybrid lines, there was not a coordinate expression of SV40 T-antigen and transformation traits. The phenotypic separation in somatic cell hybrids of SV40 T-antigen expression and transformation phenotypes and tumorigenicity is evidence that host genetic changes, occurring during or subsequent to viral integration, also contribute to the expression of those traits in SV40-transformed cells. The general inability of human SV40- transformants to form tumors in nude mice would result from their inherent nontumorigenicity and reflect the relative rarity, compared to SV40-transformed mouse cells, of those host genetic changes determining tumorigenicity. The postulated role of an interaction between viral and cellular genetic changes was supported by other results: hybrid lines formed by fusion of LNSV cells and the tumorigenic 3T3 derivative were markedly more anchorage independent than either parental line or LNSV/ 3T3 hybrid cells.
X-Y chromosome dissociation in wild derived Mus musculus subspecies, laboratory mice, and their F1 hybrids
Authors: Matsuda Y. , Imai H.T. , Moriwaki K. , Kondo K. , Bonhomme F.
Published: May 2008

The frequencies of X and Y chromosome dissociation in primary spermatocytes of wild-caught specimens of six Mus musculus subspecies, fifteen inbred mouse strains, and their F] hybrids were examined. Three different types (I, II, and III) of X-Y dissociation were identified. Type I was found in inter-subspecies hybrids (BALB/c X M. m. molossinus, M. m. bactrianus, M. m. castaneus, or M. m. urbanus), in which the X-Y dissociation was less than 20°/o in each subspecies but 60–80% in the Ft hybrids. Type II was seen in the DBA/2J and DDK strains, in which the dissociation frequency was about 30% in the homozygous condition and increased up to 50% in inter-strain hybrids (C57BL/6J X DBA/2J or DDK). Type III found in the WB/Re strain also showed high dissociation frequency (51.1%) in the homozygous condition but the value was remarkably lower (11.3%) in (C57BL/6J X WB/Re)FiS. Some Asian wild mice seem to have type II or III as well as type I.
Decreased tumorigenicity of Chinese hamster cells after fusion with tumorigenic mouse myeloid leukemia cells
Authors: Geurts van Kessel A.H.M. , de Both N.J. , Hagemeijer A.
Published: May 2008

Hybrid cell lines, derived after fusion of tumorigenic mouse and Chinese hamster cells, were assayed for their tumor forming capacity in nude mice. Partial suppression of tumorigenicity was observed in some of the hybrids tested, suggesting complementation for tumorigenicity.
In situ colony growth and cytogenetic analysis of human lymphocytes
Authors: Chaganti R.S.K. , Auerbach S.B.
Published: May 2008

A simple method is described which permits in situ culture and chromosome preparation of human lymphocytes immobilized on a glass surface. The method is useful in the analysis of clonal propagation and cytogenetics of lymphocyte subsets.
The relative DNA contents of the eutherian and marsupial X chromosomes
Authors: Hayman D.L. , Ashworth L.K. , Carrano A.V.
Published: May 2008

The relative DNA contents of individual chromosomes of Sminthopsis crassicaudata (Marsupialia) have been measured by DNA cytophotometry. Measurements of the relative nuclear DNA contents of man and Sminthopsis have been made and show that the DNA content of the marsupial X chromosome is substantially less than that of the X chromosome of man. The implications of this observation with respect to the argument of the conserved X chromosome in mammals are presented.
Conserved linkage of soluble aconitase and galactose-1-phosphate uridyl transferase in mouse and man: assignment of these genes to mouse chromosome 4
Authors: Nadeau J.H. , Eicher E.M.
Published: May 2008

Polymorphism and linkage of mouse soluble aconitase (Aco-1) and galactose-1-phosphate uridyl transferase (Gait) are reported. Three alleles at each locus were recognized on the basis of differences in electrophoretic mobility. Linkage crosses involving Aco-1, brown (b), major urinary protein (Mup-1), and the Rb(4.6)2Bnr Robertsonian translocation (Rb2) showed that Aco-1 is located on the proximal portion of chromosome 4 between (Mup-1) and the centromere. Because Aco-1 and Gait are located on the short arm of the human 9, linkage of mouse Aco-1 and Gait was thought to be likely. Linkage crosses involving Rb2, Gait, Aco-1, Mup-1, and b confirmed this expectation and established the order of loci as: centromere—Gait—Aco-1—Mup-1—b. The conserved linkage of Aco-1 and Gait in mouse and man probably represents an ancient linkage not yet disrupted by chromosomal rearrangement, rather than a linkage preserved by natural selection.
Confirmation of the mapping assignment of human serum albumin to chromosome 4 using a cloned human albumin gene
Authors: Kurnit D.M. , Wallner Philipp B. , Bruns G.A.P.
Published: May 2008

The human albumin locus (ALB) is assigned to chromosome 4 by hybridization of a cloned human albumin gene (cDNA) probe to genomic DNA’s isolated from a panel of human-rodent somatic cell hybrids.
The gene map of the rabbit, Oryctolagus cuniculus L.
Authors: Echard G. , Gellin J. , Benne F. , Gillois M.
Published: May 2008

The segregation of 11 enzyme markers was analyzed in 74 independent rabbit X hamster hybrid clones. Two syntenic groups were observed, LDHB-TPI and LDHA-ACP2. No syntenic relationship was found for the seven other markers, PEPB, PGM1, ENOl, GPI, NP, MDH1, and MDH2.
Banded chromosomes of Galago crassicaudatus monteiri, G. c. garnetti, and a subspecific hybrid
Authors: Poorman P.A.
Published: May 2008

In this report the karyotypes of Galago crassicaudatus monteiri and G. c. garnetti are described using G-banding, Q-banding, silver staining for nucleolus organizer regions and synaptonemal complex analysis. The banded chromosomes of the two subspecies are compared with each other and with a hybrid between the two subspecies. Allowing for pericentric inversions of seven autosomal pairs, the banded chromosomes of the two subspecies are indistinguishable. Comparisons with the karyotype of Cheirogaleus medius have been made.
Intersexuality associated with XX/XY mosaicism in a horned goat
Authors: Bongso T.A. , Thavalingam M. , Mukherjee T.K.
Published: May 2008

Anatomical, histological, and cytogenetic studies were undertaken on a horned intersex goat kid and three of its normal litter mates. The intersex had male type horns, male beard, vestigial mammary glands, female external genitalia, and an enlarged peniform clitoris, exuded a pungent male odor, had a male bleat, and came into estrus every 20 days. At laparotomy and subsequent slaughter, an ovotestes was observed on the right side and a testis and epididymal remnants on the left side. Uterine horn segments, cervix, vagina, and enlarged clitoris (2 cm) were also present. Histologically, spermatogenesis was not observed in either testis, but active Leydig cells were present. The ovary contained mature follicles. Chromosome analysis revealed 60XX/60XY cell populations in blood, bone marrow, and skin. Lymphocytic metaphases from the male and female cosibs showed single populations of 60XY and 60XX, respectively. Mosaicism associated with the horned condition in the intersex goat was established.
Mapping of the human gene for epidermal growth factor receptor (EGFR) on the p13→q22 region of chromosome 7
Authors: Kondo I. , Shimizu N.
Published: May 2008

We previously reported that the structural gene for epidermal growth factor receptor (EGFR) can be mapped to the p22→qter region of human chromosome 7 (Shimizu et al., 1979, 1980). In the present study, we produced two series of human-mouse cell hybrids by fusing mouse A9 cells that are deficient in EGFR with the human diploid fibroblast lines GM1356, 46, XX, t(l;7)(p34;pl3), and GM2068, 46, XX, t(6;7)(q27;q22), both of which possess EGF receptors. Expression of EGF binding ability in the former series of cell hybrids was correlated with the retention of the human translocation chromosome containing the 7p13→qter region, and in the latter series of cell hybrid it was correlated with the retention of the human translocation chromosome containing the 7pter→q22 region. Therefore, the EGFR gene can be localized in the p13→q22 region of chromosome 7.
Provisional assignment of TPI, GPI, and PEPD to Chinese hamster autosomes 8 and 9: a cytogenetic basis for functional haploidy of an autosomal linkage group in CHO cells
Authors: Siciliano M.J. , Stallings R.L. , Adair G.M. , Humphrey R.M. , Siciliano J.
Published: May 2008

Concordant segregation analysis of Chinese hamster (Cricetulus griseus) isozymes and chromosomes segregating from interspecific somatic cell hybrids made with mouse C11D cells revealed the locations of GPI and PEPD on chromosome 9 and TPI on chromosome 8 in both euploid Chinese hamster and CHO cells. The patterns of electrophoretically detectable shift mutants of these loci in CHO cells were consistent with the observed presence of two normally banded chromosome 8’s and monosomy for chromosome 9. These findings and the isolation of three independent, null PEPD mutants in only 527 ethyl methansulfonate-exposed clones indicate that the high frequency of recovery of recessive drug resistant mutants in CHO cells may be due not only to haploidy caused by deletions and monosomy but also by great sensitivity of certain loci to particular mutagens.
The Z-chromosome is involved in the regulation of H-W (H-Y) antigen gene expression in Xenopus
Authors: Engel W. , Kobel H.R.
Published: May 2008

H-W (H-Y) antigen was investigated in diploid, triploid, and tetraploid Xenopus hybrids. These hybrids differ from each other with respect to their sex chromosome constitution–they all have a single W chromosome but one to three Z chromosomes. The H-W antigen concentration is reduced with increasing numbers of Z chromosomes. In the diploid and triploid hybrids the single W chromosome is able to guarantee ovary development, but among the tetraploids both male and female animals occur. However, both sexes have identical H-W antigen titers in the somatic tissues. It can be concluded that in these tetraploid hybrids with a ZZZW sex chromosome complement, the amount of H-W antigen is too low to sustain ovary development in all cases.
Assignment of the human phosphoserine phosphatase gene (PSP) to the pter→q22 region of chromosome 7
Authors: Koch G.A. , Eddy R.L. , Haley L.L. , Byers M.G. , McAvoy M. , Shows T.B.
Published: May 2008

Phosphoserine phosphatase (PSP) catalyzes the hydrolysis of phosphoserine to serine. PSP expression has been examined in human-mouse somatic cell hybrids retaining different combination of human chromosomes. Human PSP is expressed only when the pter→q22 segment of the human 7 and its enzyme marker qβ-glucuronidase (GUSB) are retained in cell hybrids. The structural gene, PSP,is therefore assigned to this region of the human 7.
An XX male with a single STS gene dose
Authors: Wieacker P. , Voiculescu J. , Müller C.R. , Ropers H.H.
Published: May 2008

There is substantial evidence that many XX males arise from an X/Y interchange, so that a terminal Xp segment carrying the Xg locus, but not the neighboring steroid sulfatase (STS) locus, is replaced by part of the Y chromosome. We show here that one of the two X chromosomes of an XX male with low intracellular levels of STS does not express the STS gene.
A rapid DAPI-distamycin method for identification of the mouse Y chromosome
Authors: Buhariwalla F. , Blecher S.R.
Published: May 2008

In a study requiring rapid diagnosis of the chromosomal sex of mice, standard staining methods for mouse chromosomes were evaluated for speed, simplicity, and the quality of staining. None of the techniques previously used for mouse chromosomes were adequate. However, a DAPI-distamycin A method for human karyotyping was successfully adapted for this purpose.
The measurement of sister chromatid exchanges induced in utero utilizing intraperitoneal infusion of BrdU: a novel technique
Authors: Singh N.P. , Turturro A. , Chang M.J.W. , Hart R.W.
Published: May 2008

One of the inherent difficulties associated with the accurate detection of sister chromatid exchanges (SCE’s) in vivo is the maintenance of a continuous supply of 5-bromo-2’-deoxyuridine (BrdU) for differential staining of sister chromatids. We have developed a simple, reproducible intraperitoneal technique which has the advantages of continuous BrdU infusion and is less stressful than presently available methods. Additionally, a gentle trypsinization methodology was developed to obtain relatively large numbers of metaphases from fetal tissues. Using these techniques, we examined the induction of SCE by 7,12-dimethylbenz(a)anthracene (DMBA) when injected into pregnant CD rats on days 11, 13, 15, and 16 of gestation. The levels of SCE induced were slightly higher in fetal than maternal tissue, although not significantly.
A temperature sensitive mutant of a Chinese hamster cell line exhibiting high chromosomal breakage
Authors: Fainsod A. , Voss R. , Spann P. , Goitein R. , Marcus M.
Published: May 2008

A temperature sensitive mutant exhibiting a very high level of chromosomal aberrations has been isolated from the Chinese hamster cell line E36. The chromosome aberrations, which include chromosome and chromatid breaks, multiradial configurations, dicentrics, and pulverizations, start to appear 1 h after a shift in temperature from 34°C to 40.5°C. The rate of sister chromatid exchange is not increased in this mutant. Analysis of somatic cell hybrids indicates that the mutation in this temperature sensitive mutant is dominant.
Assignment of the gene for neutral alpha-glucosidase AB to chromosome 11
Authors: Martiniuk F. , Smith M. , Ellenbogen A. , Desnick R.J. , Astrin K. , Mitra J. , Hirschhorn R.
Published: May 2008

Human tissues contain two isozymes of neutral a-glucosidase, neutral a-glucosidase AB and neutral a-glucosidase C (a-D-glucoside glucohydrolase, EC 3.2.1.20). The two isozymes, initially defined on the basis of differences in electrophoretic mobility in starch gel, have also been shown to have other distinguishing biochemical characteristics including different substrate specificites. Rodent tissues contain apparently homologous isozymes of neutral a-glucosidase. The mouse and human a-glucosidase C isozymes, but not the AB isozyme(s), can be distinguished by the difference in their electrophoretic mobility. This difference has previously enabled us to use human-mouse somatic cell hybrids to assign the structural gene for human a-glucosidase C to chromosome 15. We now report the differentiation of mouse and human neutral a-glucosidase AB isozymes by rocket immunoelectrophoresis, using an antibody raised in mice against purified human placental neutral a-glucosidase AB. This antibody precipitated both the A and B bands of human neutral a-glucosidase AB and did not cross react with mouse enzyme as determined by Ouchterlony double immunodiffusion and by rocket immunoelectrophoresis. Using this antibody, the segregation of human neutral a-glucosidase AB was examined in 41 mouse x human hybrid clones. Thirty-eight hybrid clones, derived from fusions of RAG x seven different human cells, showed 100% concordant segregation of human neutral a-glucosidase AB and the 11. Three additional clones, derived from a fusion of tetraploid murine erythroleukemia cells (2S-MEL) x diploid human fibroblasts carrying a translocation chromosome(s) allowed the regional localization of the gene to the long arm of 11 (11q13→11qter).
Molecular cytogenetics of the Equidae
Authors: Gadi I.K. , Ryder O.A.
Published: May 2008

A (G + C)-rich satellite DNA component (p= 1.716 g/ml) has been fractionated from the total DNA of the Iranian subspecies of the Asiatic wild ass, Equus hemionus onager, by successive dactinomycin-CsCl and netropsin sulfate-CsCl isopycnic gradients. Complementary 3H-RNA (cRNA) transcribed from the satellite DNA hybridized predominantly to the centromeric and telomeric constitutive heterochromatic regions of onager chromosomes. These studies have suggested that satellite DNA’s with similar sequences are present in the centromeric, as well as telomeric, heterochromatic regions of some onager chromosomes. The centromeric region of the fusion metacentric t(23;24) of the onager is deficient in sequences homologous to the onager 1.716 g/ml satellite DNA, indicating a loss of satellite DNA during fusion or an amplification of the satellite DNA in the centromeric regions of the acrocentric chromosomes 23 and 24 subsequent to fission. Sequences complementary to onager 1.716 g/ml satellite DNA show extensive hybridization to the constitutive heterochromatin of the feral donkey (E. asinus) karyotype, consistent with a view of conservation and amplification of similar or identical sequences in the two species.
Chromosomal homologies and phylogenetic relationships of the vespertilionid bat genera Euderma, Idionycteris, and Plecotus
Authors: Stock A.D.
Published: May 2008

The phylogenetic relationships of three plecotine bat genera were studied by comparison of chromosome banding patterns. The G-banded karyotypes of Euderma maculatum and Idionycteris phyllotis were found to be very similar, differing by only two pericentric inversions. Plecotus townsendii possessed a strikingly different G-band karyotype, which differed from that of Euderma and Idionycteris by several fusions and an inversion in the X chromosome. Only five pairs of biarmed chromosomes and two pairs of small acrocentric chromosomes were shared as direct homologs between Plecotus and the other two genera. These results indicate a more complex derivation for the Plecotus karyotype than indicated by Williams et al. (1970) or Bickham (1979). The degree of non-matching of biarmed chromosomes indicates that the ancestor that gave rise to the Plecotus line and the Eudermaj Idionycteris line possessed a karyotype with at least 15 pairs of telocentric or acrocentric chromosomes and a diploid number of at least 42. This ancestral line may have been characterized by a Myotis-like karyotype. The plecotine genera are related to Myotis as evidenced by the possession of all four biarmed chromosomes found in that genus. The occurrence of the same small biarmed chromosome in Idionycteris, Euderma (11), Plecotus (10), and Myotis (16/17 of Bickham) clearly unites the plecotine genera with the Myotis group in contrast to the opinion of Williams et al. (1970). This chromosome is believed to be the result of an inversion in an acrocentric chromosome of the original vespertilionid karyotype of 50 or more telocentric or acrocentric chromosomes as seen in the genus Eptesicus. The data derived from these comparisons are presented cladistically to make the information more accessible to systematic zoologists.
A presumptive new hylobatid subgenus with 38 chromosomes
Authors: Prouty L.A. , Buchanan P.D. , Pollitzer W.S. , Mootnick A.R.
Published: May 2008

The gibbon Hylobates hoolock has been found to possess a karyotype different in diploid number and banding pattern from that of any other hylobatid. We propose that the hoolock gibbon occupy its own subgenus in the genus Hylobates.
Nucleolar organizer regions in Akodon arviculoides (Cricetidae, Rodentia): evidence for the activity of rDNA genes in both X chromosomes of females
Authors: Yonenaga-Yassuda Y. , de Assis M.F.L. , Kasahara S. , L’Abbate M. , Souza M.J.
Published: May 2008

Silver-stained cells from 13 specimens of Akodon arviculoides (2n = 14 and 15) were analyzed for the location and frequency of Ag-NOR’s. They were located terminally on four pairs of chromosomes, 3q, 4q, 5p, and Xp. In these 13 individuals, the number of Ag-NOR’s per cell varied between two and eight, and each chromosome had a characteristic pattern of frequency of NOR’s in each individual. Since in A. arviculoides a chromosomal polymorphism resulting from three autosomal pericentric inversions in chromosomes 2, 3, and 5 and a complex rearrangement involving chromosome 1 exist, it was possible to determine the frequency of Ag-staining in each homologue of these pairs in heterozygous individuals. Both X chromosomes had active NOR’s in the females. An Ag-NOR was also present on the single X chromosome of the males.
High-resolution banding by treating cells with acridine orange before fixation
Authors: Matsubara T. , Nakagome Y.
Published: May 2008

Treatment of standard blood cultures with acridine orange (20–25 ug/ml) during the final 30 min of culture, 30–90 min after the addition of Colcemid, provides a simple method for obtaining elongated human chromosomes for high-resolution trypsin-Giemsa banding.
DNA replication and sister chromatid exchange in 9qh+
Authors: Crossen P.E.
Published: May 2008

The frequency of sister chromatid exchanges (SCE’s) in the euchromatin and heterochromatin of a human 9qh+ chromosome was determined using the BrdU-Giemsa technique. The 9qh+ region contained fewer exchanges than the euchromatin, and there was an excess number of exchanges at the junction of the euchromatin and heterochromatin of the long arm. BrdU incorporation and differential staining of sister chromatids showed that the heterochromatic region of the 9 was always the last region to replicate and was among the last areas of the whole human chromosome complement to complete replication.
Chromosome changes in 6-TG-resistant mutant strains derived from a karyotypically stable human line, C32
Authors: Chen T.R.
Published: May 2008

Karyotypes of the human C32r16 line and its HPRT” mutant derivatives were compared. All three HPRT- mutant strains (TG-A, TG-E1, and TG-E2) studied were hypotetraploid and arose by genomic duplication. TG-A and TG-E had distinct karyotypes, reflecting their independent clonal origins. Both TG-E1 and TG-E2 were similar karyotypically, except that TG-E2 differed from TG-E1 by the presence of two new sets of balanced translocations and a significantly higher number of new markers, viz., 24 new markers in 14 TG-E2 cells as compared to 2 new markers in 13 TG-E1 cells. Comparison of the hypothetical 2s karyotype of C32r16 with the modal karyotypes of the mutants revealed (1) that chromosome changes occurred more frequently among marker chromosomes (57.1%) than among normal chromosomes (18.1%) and also more frequently among tetrasomic (28.6%) than among disomic (3.3%) normal chromosomes, and (2) that one member of a group of paired marker chromosomes tended to be eliminated very frequently, whereas disomic normal chromosomes retained their disomic condition. Chromosome 7 was involved in the formation of new marker chromosomes twice as much as any other chromosome, and even increased to pentasomy in TG-E1. Chromosome changes associated with 6-thioguanine treatment are briefly discussed.
Karyotypic kinship between the blue fox (Alopex lagopus Linn.) and the silver fox (Vulpes fulva Desm.)
Authors: Yoshida M.A. , Takagi N. , Sasaki M.
Published: May 2008

A karyotypic comparison between the blue fox and the silver fox revealed conservation of the chromosome arm as a unit, except for large heterochromatic blocks in 10 pairs of blue fox chromosomes and the complete absence of a common metacentric autosomal pair. This finding seems to indicate that their karyotypes evolved from a common ancestral karyotype, characterized by 70–76 acrocentric autosomes, mainly through a series of independent centric fusions.
The ancestral karyotype of Carnivora: comparison with that of platyrrhine monkeys
Authors: Dutrillaux B. , Couturier J.
Published: May 2008

The karyotypes of six species of Carnivora (Mungos mungo, Paradoxurus hermaphroditus, Potos flavus, Mustelafuro, Felis serval, and Halichoerus grypus), representative of five different families, were studied and compared. Correspondence between almost all chromosome segments was found, and a presumed ancestral karyotype of Carnivora is proposed. Analogies to human chromosomes are also given, and the results obtained are in excellent agreement with previously published gene mapping data on man and the domestic cat.