Showing papers in "Cytogenetic and Genome Research in 1969"
TL;DR: The hindquarters of two batches each of five young adult male mice were exposed to an acute dose of 1,200 R of 250-kV X-rays in two fractions of 600 R, separated by a period of eight weeks.
Abstract: The hindquarters of two batches each of five young adult male mice were exposed to an acute dose of 1,200 R of 250-kV X-rays in two fractions of 600 R, separated by a period of eight weeks. Means of 4
104 citations
TL;DR: The karyotypes of 15 species of snakes are described: Lachesis muta noctivaga, Micrurus lemniscatus carvalhoi, Philodryas aestivus aestivu, and so on.
Abstract: The karyotypes of 15 species of snakes are described: Lachesis muta noctivaga , Micrurus lemniscatus carvalhoi , Philodryas aestivus aestivus , &l
101 citations
TL;DR: Genetic studies have shown that the dominant gene for polledness found in the Saanen breed will, when homozygous, lead to pseudohermaphrodism, testicular hypoplasia or epididymal sperm granuloma and infertility.
Abstract: Genetic studies have shown that the dominant gene for polledness found in the Saanen breed will, when homozygous, lead to pseudohermaphrodism, testicular hypoplasia or epididymal sperm granuloma and t
77 citations
TL;DR: The study of a bovine freemartin and its male co-twin has shown that the sex-reversed gonads of the female are secreting testosterone, and it is suggested that the masculinisation of the freemARTin is masculinised.
Abstract: The study of a bovine freemartin and its male co-twin has shown that the sex-reversed gonads of the female are secreting testosterone. Therefore, we suggest that the masculinisation of the freemartin’
60 citations
TL;DR: Quantitative study has been carried out of the conditions under which exposure of Chinese hamster cells to Colcemid produces polyploidy, chromosomal aneuploidsy and cell killing.
Abstract: 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 c
56 citations
TL;DR: In vitro studies were carried out on kidney epithelial cells and fibroblasts of female Microtus agrestis and fibrobasts of male and female Cricetulus gr.
Abstract: In vitro studies were carried out on kidney epithelial cells and fibroblasts of female Microtus agrestis and fibroblasts of male and female Cricetulus gr
41 citations
TL;DR: A phenotypically normal male mouse, investigated because it was sterile, was found to possess 41 chromosomes, and a karyotypic analysis indicated the extra element was one of the smallest chromosomes, almost certainly the Y.
Abstract: 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.
38 citations
TL;DR: Examination of 154 specimens representing nine species of the genus Neotoma revealed diploid numbers of 38, 52, 54 and 56, and extensive polymorphism was found in two species.
Abstract: Examination of 154 specimens representing nine species of the genus Neotoma revealed diploid numbers of 38, 52, 54 and 56. Six species had the diploid number of 52. Extensive polymorphism was found in two species, N. lepida and N. micropus. Chromosomal variation in the subgenus Neotoma was primarily in Fundamental Number and not in diploid number.
38 citations
TL;DR: The karyo types of five turtles of the genus Podocnemis from the Amazon Region of Brazil were determined and four species were determined.
Abstract: The karyo types of five turtles of the genus Podocnemis from the Amazon Region of Brazil were determined. Four species, P . cayennensis, P . <
36 citations
TL;DR: It is demonstrated that sex chromatin appears in cells of pre-implantation blastocysts of the domestic rabbit over a period from approximately 96 to 120 hours after mating of the parent animals.
Abstract: It is demonstrated that sex chromatin appears in cells of pre-implantation blastocysts of the domestic rabbit over a period from approximately 96 to 120 hours after mating of the parent animals. We ar
35 citations
TL;DR: The results indicate that constriction length depends on the amount of genome and that the deletion is limited to the constricted segment, supporting the view that the constriction is the nucleolar organizer.
Abstract: Secondary chromosomal constrictions are thought to be the loci of the genome which code for ribosomal RNA synthesis. Their metaphase length could depend on nucleolar size or level of functional activity in interphase or on gene content. Wild-type frogs and a frog heterozygous for the Oxford nucleolar mutation were studied to determine which possibility is more probable. The mutant was studied because its single nucleolus is larger than wild-type nucleoli, it has only one constriction, half as many ribosomal genes, but produces the same amount of ribosomal RNA. The results indicate (1) that constriction length depends on the amount of genome (whereas others have shown nucleolar size to be related to level of activity) and (2) that the deletion is limited to the constricted segment, supporting the view that the constriction is the nucleolar organizer. Also, metaphase constrictions are longer than expected from their DNA content.
TL;DR: DNA replication studies were carried out on metaphase plates showing satellite associations to determine the association of individual D chromosomes.
Abstract: DNA replication studies were carried out on metaphase plates showing satellite associations to determine the association of individual D chromosomes. In a total of 279 D chromosomes involved in satell
TL;DR: The possibility is raised that the Y chromosome of mammals carries genetic information essential for normal spermatogenesis, as distinct from its established function in embryonic gonadal determination.
Abstract: A sterile mouse was found to be a chromosomal mosaic with two cell lines, one containing 39 chromosomes, the other 41. Both types were present in approximately equal numbers in the bone marrow, but the 41-chromosome line alone was identified in spermatogonia and spermatocytes. Evidence from chromosome morphology at mitotic metaphase and from spermatocytes at diakinesis and metaphase I identified the two cell-lines as XO and XYY respectively. The alternative possibilities of exclusion of the XO line from the seminiferous elements by chance and by selection are discussed and the latter interpretation favoured. The possibility is raised that the Y chromosome of mammals carries genetic information essential for normal spermatogenesis, as distinct from its established function in embryonic gonadal determination.
TL;DR: Evidence is presented for an XX/XY sex-determining mechanism in five species of the genus Uta and all species examined have a somatic diploid complement of 12 macrochromosomes and 22 mDNA.
Abstract: Evidence is presented for an XX/XY sex-determining mechanism in five species of the genus Uta . All species examined have a somatic diploid complement of 12 macrochromosomes and 22 m
TL;DR: Acute and chronic studies of male and female meiosis in an Imperial-Chemical-Industries-derived strain of mice were carried out with LSD-25, finding a wide range of doses claimed to be effective in teratology.
Abstract: Acute and chronic studies of male and female meiosis in an Imperial-Chemical-Industries-derived strain of mice were carried out with LSD-25. Over a wide range of doses claimed to be effective in terat
TL;DR: A proband girl was investigated because of a congenital heart defect and hexadactyly and satellites were found on in the patient.
Abstract: A proband girl was investigated because of a congenital heart defect and hexadactyly. Her brother and sister died in early infancy from cardiac malformations. In the patient, satellites were found on
TL;DR: It appears that the shorter culture time enhances clone detection, as six cytogenetically aberrant clones were found in 5 of the 17 exposed survivors and four were detectable on the basis of the two-day culture results alone.
Abstract: 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.
TL;DR: Five closely related Romney sheep are described and one sheep, a ram, had abnormally shaped testicles, which showed centric fusion of two acrocentric chromosomes, forming a submetacentric chromosome.
Abstract: Five closely related Romney sheep are described All showed centric fusion of two acrocentric chromosomes, forming a submetacentric chromosome One sheep, a ram, had abnormally shaped testicles, was s
TL;DR: An attempt was made to confirm the linear dose-effect kinetics reported by H. J. Evans for the production of two-break aberrations in X-irradiated human leukocyte cultures fixed after 52 to 56 h incubation.
Abstract: An attempt was made to confirm the linear dose-effect kinetics reported by H. J. Evans for the production of two-break aberrations in X-irradiated human leukocyte cultures fixed after 52 to 56 h incub
TL;DR: Chromosomes from seven species of Tupaiidae, including Tupaia glis , T. chinensis, T. longipes, and T. montana are studied.
Abstract: Chromosomes from seven species of Tupaiidae, including Tupaia glis , T. chinensis , T. longipes , T. montana , T. minor
TL;DR: Measurement of the B-group short arms from 25 cases and five balanced carriers with a Bp– chromosome showed a significant clustering of the size of the deleted short arm between 0.45 and 0.65 of the normal short-arm length.
Abstract: Measurement of the B-group short arms from 25 cases and five balanced carriers with a Bp– chromosome showed a significant clustering of the size of the deleted short arm between 0.45 and 0.65 of the normal short-arm length. No differences in length were apparent among family members when the deletion was familial. The distribution of deletion size appeared similar for chromosome 4 and chromosome 5. No correlation was found between any clinical feature and the length of the deleted short arm. The results are discussed in relation to the origin of deletions – simple terminal or interstitial deletions or reciprocal translocations.
TL;DR: A family with a normal chromosome complement plus a tiny centric fragment with satellites on both arms in some of the members in which the proband was a child with regular G1 tri.
Abstract: We present a family with a normal chromosome complement plus a tiny centric fragment with satellites on both arms in some of the members in which the proband was a child with regular G1 tri
TL;DR: Clinical, cytogenetic and other laboratory studies are reported in a set of dizygous twins, their parents and siblings.
Abstract: Clinical, cytogenetic and other laboratory studies are reported in a set of dizygous twins, their parents and siblings. The proposita was a girl with profound mental deficiency of unknown cause; she had been born with a placenta showing marked chorangiomatosis. In addition, she was found to have a chromosomal error consisting of a translocation of material of the long arms of a No. 2 chromosome to the long arm of a No. 15 chromosome. Studies of normal marker loci failed to provide evidence that any of them had been lost or inactivated as a consequence of the translocation.
TL;DR: The Y chromosome of the Chinese hamster is late replicating in spermatogonial mitoses labelled in vivo and during the last two hours of the S phase the long arm of the Y replicates the Y.
Abstract: The Y chromosome of the Chinese hamster is late replicating in spermatogonial mitoses labelled in vivo. During the last two hours of the S phase the long arm of the Y replicates the majority of its DNA. The short arm terminates replication before this. Replication of the long arm of the X takes place earlier in S, whereas the short arm of the X is synchronous with that of the Y. Two small metacentric autosomes are also late replicating, in synchrony with the long arm of the Y. The distinct pattern of late replication of the Y chromosome of spermatogonia is in agreement with our experience with other mammals. The replication patterns of spermatogonia and a morphological study of the XY bivalent in primary spermatocytes indicate that the X and Y chromosomes pair by their short arms.
TL;DR: A previously unreported type of male pseudohermaphrodite sheep is described, which had XY sex chromosomes in all tissues studied and was chromatin negative.
Abstract: A previously unreported type of male pseudohermaphrodite sheep is described. The animal had XY sex chromosomes in all tissues studied and was chromatin negative. It had female external genitalia and u
TL;DR: By this method, with computer assistance, a method enabling associations between acrocentrics to be determined without recourse to any subjective measurements is used.
Abstract: In this study we have used a method enabling associations between acrocentrics to be determined without recourse to any subjective measurements. By this method, with computer assistance, we were able
TL;DR: The taxonomic status of M. shawi and M. libycus is evaluated with respect to the chromosomal and hybridization data, and the isolating mechanisms involved with speciation in Meriones ate considered.
Abstract: Laboratory hybridization has been achieved between two partially sympatric species of jird, Meriones shawi (2n = 44) and M. libycus (2n = 44). The parental karyotypes differ by at least three autosomal rearrangements and a remodeling of the X chromosome. F1 hybrid karyotypes contain a haploid set derived from each parent, and the species origin of four chromosomes, including the X, can be identified. The FI females are fertile, whereas F1 males are infertile owing to completely or markedly diminished spermatogenesis. The F1 females backcrossed with M. shawi males are fertile and produce normal-sized litters with normal sex ratios; male progeny from this cross have normal spermatogenesis and are fertile. The F1 females backcrossed with M. libycus males exhibit reduced fertility, small litters and an absence of male offspring. The taxonomic status of M. shawi and M. libycus is evaluated with respect to the chromosomal and hybridization data, and the isolating mechanisms involved with speciation in Meriones ate considered.
TL;DR: A high frequency of spontaneous chromosomal aberrations was found in a phenotypically normal female with no history of either radiation therapy or clinical abnormalities.
Abstract: A high frequency of spontaneous chromosomal aberrations was found in a phenotypically normal female with no history of either radiation therapy or clinical abnormalities. The aberrations appear to be
TL;DR: Minute deletions of the B-group short arm have been demonstrated in five of six cases with clinical features suggestive of a deletion of chromosome 4 or 5, but with grossly normal chromosomes.
Abstract: Minute deletions of the B-group short arm have been demonstrated in five of six cases with clinical features suggestive of a deletion of chromosome 4 or 5, but with grossly normal chromosomes. A delet
TL;DR: A method of recording sex chromatin scores with a reproducibility of ±3% at two standard deviations is described and in 25 clinically normal women (control group) the frequency of sex Chromatin was 40.8.
Abstract: A method of recording sex chromatin scores with a reproducibility of ±3% at two standard deviations is described. In 25 clinically normal women (control group) the frequency of sex chromatin was 40.8