Showing papers on "X chromosome published in 1969"
Journal Article•
643 citations
TL;DR: Results indicate that glucose-6-phosphate dehydrogenase from a mouse oocyte is an X-linked enzyme, that its synthesis occurs in the oocyte and is dosage dependent, and that inactivation of the X chromosome does not occur in the mouse oocytes.
Abstract: The glucose-6-phosphate dehydrogenase and lactate dehydrogenase contents of oocytes from XO and XX female mice have been measured. The activity of the former in the oocytes of XO mice is half of that in the oocytes of XX mice, whereas the lactate dehydrogenase activities in the two groups of ova are the same. These results indicate that glucose-6-phosphate dehydrogenase from a mouse oocyte is an X-linked enzyme, that its synthesis occurs in the oocyte and is dosage dependent, and that inactivation of the X chromosome does not occur in the mouse oocyte.
148 citations
TL;DR: An anomalous sex-chromosome constitution was observed by chance in a case of phenotypically normal female golden hamster in which 44 chromosomes with a karyotype which was indistinguishable in general appearance from that of the normal male.
Abstract: An anomalous sex-chromosome constitution was observed by chance in a case of phenotypically normal female golden hamster. Bone marrow metaphases of this animal showed 44 chromosomes with a karyotype which was indistinguishable in general appearance from that of the normal male. Two tentative interpretations were made for the sex-determining mechanism of the present specimen: one is the XY constitution in which the Y chromosome had lost its male factors due to the interchange of genetic materials between the X and the Y at the time of meiotic segregation, and the other deals with a partial short arm deletion in one of the two X chromosomes.
92 citations
TL;DR: In this article, the mouse X-chromosome controlling elements, detected by their influence on the position effect variegation caused by the X-autosome translocation T (1; X) Ct, have been found to modify the heterozygous phenotypes of two X-linked genes.
Abstract: The mouse X-chromosome controlling elements, detected by their influence on the position effect variegation caused by the X-autosome translocation T (1; X) Ct, have been found to modify the heterozygous phenotypes of two X-linked genes. It is proposed that X-inactivation can be incomplete, the level of inactivation or the frequency of cells in which inactivation is incomplete being dependent upon the ‘state’ of the controlling element located in the X. The data suggest that this is a consequence of a reversal, or partial reversal, of inactivation of the X as a whole in some cells rather than a vairable spread of inactivation along the length of the X.
76 citations
TL;DR: It is suggested that dosage compensation in Drosophila is achieved chiefly by a hyperactivity of the male X, in contrast to the single X inactivation in female mammals, and that this hyperactivity is expressed visibly in the morphology and metabolic activity of the X -chromosome in the larval salivary glands of themale.
Abstract: Morphology and the rate of RNA synthesis of the X -chromosome in XX/XO mosaic larval salivary glands of Drosophila melanogaster have been examined. For this purpose the unstable ring- X was utilized to produce XX and XO nuclei in the same pair of glands. The width of the X -chromosome and the left arm of the 3rd chromosome (3 L ) of larval salivary glands was measured and the rate of RNA synthesis by them was studied upon the use of [ 3 H]uridine autoradiography in such XX (female) and XO (male) nuclei developing in a female background (i.e. otherwise genotypically XX ). In such mosaic glands the width of the single X -chromosome of male nuclei is nearly as great as that of the paired two X 's of female nuclei, as is also the case in normal male ( X Y ) and female ( XX ). The single X of male nuclei synthesizes RNA at a rate equal to that of the paired two X 's of female nuclei and nearly twice that of an unpaired X of XX nuclei. Neither the developmental physiology of the sex nor the proportion of XO nuclei in a pair of mosaic salivary glands of an XX larva has any influence on these two characteristics of the male X -chromosome. It is suggested that dosage compensation in Drosophila is achieved chiefly, if not fully, by a hyperactivity of the male X , in contrast to the single X inactivation in female mammals, that this hyperactivity of the male X is expressed visibly in the morphology and metabolic activity of the X -chromosome in the larval salivary glands of the male, and that this hyperactivity and therefore dosage compensation in Drosophila in general is not dependent on sex-differentiation, but is a function of the doses of the X -chromosome itself.
62 citations
TL;DR: A comparison of the X chromosome puffing patterns of male and female larvae failed to show any qualitative differences although in the males a group of puffs were active for a longer time during development than in females.
Abstract: Salivary gland X chromosome puffing patterns are described for the Oregon stock of Drosophila melanogaster and for the Berkeley stock of D. simulans. In D. melanogaster regular phase specific puffing was recorded at 21 loci in the third larval instar and subsequent prepupal stage. A comparison of the X chromosome puffing patterns of male and female larvae failed to show any qualitative differences although in the males a group of puffs were active for a longer time during development than in females. The X chromosome puffing patterns of D. simulans are similar to those described for D. melanogaster although two puffs (4F 1–4 and 7B 1–3) were active in D. simulans but not in D. melanogaster. The sex differences in puffing observed in D. melanogaster were also observed in D. simulans.
62 citations
TL;DR: These patients are the first recognized examples of dysgammaglobulinemia associated with a chromosomal deletion of the long arm of the same chromosome.
Abstract: IN CONTRAST to the X chromosome, little is known about the autosomal loci for various genetic traits. Recently Gerald et al1 and Bloom et al 2 have presented suggestive evidence that the controlling formation of locus the α-chain of haptoglobin is situated on one end of a No. 13 chromosome. We have studied two patients with chromosome defects and dysgammaglobulinemia. One had a No. 18 ring chromosome, which is formed by breakage in both arms with reunion of the broken ends and loss of a variable amount of material distal to each break. The other had a partial deletion of the long arm of the same chromosome. In both patients IgA was not detectable, and, in one, the level of IgG was very low. These patients are the first recognized examples of dysgammaglobulinemia associated with a chromosomal deletion. Report of Cases Case 1.—A 3-year-old white boy was first admitted to
61 citations
TL;DR: SEX is determined by the presence of X and Y sex chromosomes in the house fly, Musca domestica L. (males are heterogametic), and the Y chromosome determines maleness.
Abstract: SEX is determined by the presence of X and Y sex chromosomes in the house fly, Musca domestica L. (males are heterogametic), and the Y chromosome determines maleness. Aneuploid house flies with from one to six X chromosomes (and with the normal five pairs of autosomes) are females if no Y chromosome is present and males if one or more Y chromosomes are present1.
60 citations
TL;DR: It is postulated that the presence of two Y chromosomes, rather than the absence of an X chromosome, may produce differences between YY and XY male fish.
27 citations
TL;DR: If one of the X chromosomes in the female mule is inactivated at random and if this inactivation can be recognized by a delay in its DNA synthesis3–5, then about 50% of cells should show a late replicating XH and 50 per cent aLate replicating XD.
Abstract: THE mule (2n=63) is a hybrid between a jack donkey (Equus asinus, 2n=62) and a mare (E. caballus, 2n=64). The two chromosome complements are quite distinct, and in particular the X chromosomes differ morphologically; the donkey X (XD) is submetacentric and the horse X (XH) is metacentric (Fig. 1). It has also been shown that the glucose-6-phosphate dehydrogenase (G6PD) locus is X-linked in both1,2. The electrophoretic phenotype consists of a fast and slow band in both species, the G6PD of the donkey moving faster than the G6PD of the horse (Fig. 2). If one of the X chromosomes in the female mule is inactivated at random and if this inactivation can be recognized by a delay in its DNA synthesis3–5, then about 50 per cent of cells should show a late replicating XH and 50 per cent a late replicating XD. Furthermore, the G6PD pattern in the mule should consist of three bands, a fast G6PD-donkey, a mixed intermediate band corresponding to the slow G6PD-donkey plus the fast G6PD-horse and finally a slow G6PD-horse (Fig. 2).
26 citations
TL;DR: In interpreting Williams's own experience it is important to bear in mind his opinion that " a prolonged period may be necessary for repair of the initial damage to the liver after the iron has been removed and further accumulation prevented."
TL;DR: Ohno et al. as discussed by the authors suggested that random differentiation of X chromosomes indeed takes place, even when the X-homologues appear structurally modified, even though the single-active-X hypothesis is applicable to systems involving an X/X chromosome translocation has remained to be seen.
Abstract: The phenotypic effects of an X/autosome translocation in mice were among the chief sources of evidence that led to the formulation of the single-active-X hypothesis (Lyon, 1961 ; Russell, 1961 ; Russell, 1963). Even though cytological examinations of such a stock of mice have shown an X-autosome insertion (Ohno & Cattanach, 1962) rather than a typical translocation, reports are available to suggest the occurrence of X/autosome translocations in humans (Mann, Valdmanis, Capps & Puite, 1965; Mukherjee & Burdette, 1966), as well as in other stocks of mice (Ohno & Lyon, 1965). Recent studies have also shown that, in the cow, the segments of an autosome may be translocated simultaneously to an X-chromosome and an autosomal member of the complement (Gustavsson, Fraccaro, Tupolo & Lindsten, 1968). The individual X-chromosomes of all these X autosome translocation bearing mammals do not suggest a random mode of differentiation in accordance with the single-active-X hypothesis. Whether or not this hypothesis is applicable to systems involving an X/X chromosome translocation has remained to be seen. I n this communication, cytological studies are presented from a human female who exhibited a few specific stigmata of Turner’s syndrome. She had two major populations of cells with respect to X-chromosome constitution. One population of cells conformed with 45, XO-chromosome distribution. The structural changes in the X-chromosomes of the other cell population were interpreted as 46 XjX translocation types. It is suggested that random differentiation of X chromosomes indeed takes place, even when the X-homologues appear structurally modified.
TL;DR: The Y chromosome heterochromatin in Rumex thyrsiflorus has been analyzed and autoradiography with tritiated thymidine showed that chromocentres formed by Y chromosomes in interphase nuclei retain theirheterochromatic form during DNA replication.
Abstract: The Y chromosome heterochromatin in Rumex thyrsiflorus has been analyzed. In natural populations the Y chromosome shows a higher morphological variability than the X chromosome. The total duration of replication of Y chromosomes is about 2 hrs longer than that of euchromatin. Autoradiography with tritiated thymidine showed that chromocentres formed by Y chromosomes in interphase nuclei retain their heterochromatic form during DNA replication. — Y chromosome heterochromatin in interphase nuclei is stained pink, while the rest of the nucleus stains green after fast green-eosin staining for histones. — During the premeiotic stage of PMC development Y chromosomes are no longer visible as compact bodies and become more fuzzy in appearance. A diffuse state of Y coincides with intense RNA synthesis. Therefore genetic activity of Y chromosomes or their parts during premeiotic stage of microsporogenesis is postulated.
TL;DR: The DNA replication sequence in sex chromosomes of female and male cells of Melandrium album suggests that their pattern is similar to that of mammalian sex chromosomes.
Abstract: DNA replication patterns in somatic cells of female and male Meladrium album were studied with autoradiographic methods. The S-period and the average generation time have been estimated to be 5.7 and 15.5 hours respectively. The heterochromatin observed in interphase nuclei may represent the late replicating and presumably inactivated sex chromosome.One arm of one X chromosome is late replicating in females. In the Y chromosome a region near the centromere replicates late in the S-period. The DNA replication sequence in sex chromosomes of female and male cells of Melandrium album suggests that their pattern is similar to that of mammalian sex chromosomes.
TL;DR: Autoradiographic studies of incorporation of amino acids indicates that histone labelling occurs during chromosome replication, but a lag in amino acid incorporation suggests that DNA replication in the X chromosome, while accompanied, or closely followed by complexing with histone, is not necessarily coupled with its synthesis.
Abstract: The X chromosome of the Rehnia spinosus (Orthoptera) spermatocyte exists in a vesicle separate from the rest of the nucleus during its replication. This chromosome is typically heterochromatic, and late replicating. After replication the chromosome vesicle fuses with the nucleus. Cytophotometric determination of DNA and histone during replication of the chromosome revealed two types of histone. One class increases in amount in proportion to the DNA. The second class remains constant as DNA doubles, and probably increases later. Autoradiographic studies of incorporation of amino acids indicates that histone labelling occurs during chromosome replication. However, a lag in amino acid incorporation suggests that DNA replication in the X chromosome, while accompanied, or closely followed, by complexing with histone, is not necessarily coupled with its synthesis.
TL;DR: The chromosome complement of 2 male and 15 female adult squirrel monkeys (Saimiri sciureus) have been studied in peripheral blood and kidney cultures and bone marrow preparations and a female and male karyotype is presented.
Abstract: The chromosome complement of 2 male and 15 female adult squirrel monkeys (Saimiri sciureus) have been studied in peripheral blood and kidney cultures and bone marrow preparations. The diploid chromosome number is 44. Six of the chromosome pairs are metacentric (isobrachial), 9 pairs submetacentric (heterobrachial) and the remaining 6 pairs are acrocentric (cephalobrachial). The X chromosome is the longest submetacentric (heterobrachial), ranking 5 in order of decreasing size. The Y chromosome is the smallest acrocentric (cephalobrachial) of the complement. A female and male karyotype is presented.
TL;DR: A 17‐year‐old girl with several stigmata of gonadal dysgenesis and a 45, X/46, XXq˜ mosaicism is presented, and she had small hypoplastic ovaries and regular menstruations, and a lymphocytic thyroiditis.
Abstract: Gonadal dysgenesis with lymphocytic thyroiditis and deletion of the long arm of the X chromosome
TL;DR: Using female mice, heterozygous for the Cattanach translocation, it was shown that a “late labelling” X chromosome occurs in normal somatic cells of the mouse and was interpreted as supporting evidence for the postulate of random inactivation of the maternal and paternal X chromosomes.
Abstract: EVANS et al.1 have shown that a “late labelling” X chromosome occurs in normal somatic cells of the mouse. Using female mice, heterozygous for the Cattanach translocation, in which an autosomal segment is inserted into an X chromosome making the translocated chromosome (Xt) recognizable as the longest member of the complement2, they showed that this abnormally long chromosome was “hot” in about half the cells that contained a late-labelling chromosome. In the remaining cells, the hot chromosome was always one of the long chromosomes and was presumed to be the Xn chromosome. These observations were interpreted as supporting evidence for the postulate of random inactivation3 of the maternal and paternal X chromosomes.
TL;DR: Sister-sister, brother-brother and sister-brother similarities in both tibial length and stature from one month through 10 years are in accord with the hypothesis of partial X-linkage and the complex that is body length is suited to simplistic analysis.
Abstract: Sister-sister, brother-brother and sister-brother similarities in both tibial length and stature from one month through 10 years are in accord with the hypothesis of partial X-linkage, they reject the hypothesis of selective inactivation of an X chromosome, and they indicate that the complex that is body length is suited to simplistic analysis.
01 Dec 1969
TL;DR: Similar studies with normal female lymphocytes also showed a labelling pattern that mimicked that of 3H-thymidine, which interested me—for several years ago I carried out a similar experiment.
Abstract: CHERNICK'S1 demonstration of apparent late synthesis of protein on the X chromosome of female lymphocytes labelled with 3H-arginine1 interested me—for several years ago I carried out a similar experiment. The studies were done on an individual with an iso-X chromosome so that there was no question of the identification of the late replicating X chromosome. Lymphocytes were grown in culture with phytohaemagglutinin and, after 72 h, 25 µCi/ml. of 3H-arginine (Schwarz BioResearch, Inc.) and 0.1 µg/ml. of colchicine were added to the culture. Three h later the cultures were collected, treated with hypotonic, fixed in acetic acid–methanol and flame-dried. They were then stained with aceto-orcein, covered with Kodak AR-10 stripping film, and autoradiographed for 48 days. The iso-X chromosome was late labelled (Fig. 1) in a pattern identical to that seen with 3H-thymidine. Similar studies with normal female lymphocytes also showed a labelling pattern that mimicked that of 3H-thymidine.
TL;DR: The G-6-PD activity was increased during the secretory phase of the menstrual cycle, but there was no significant change in the frequency of Barr bodies or drumsticks, suggesting the hormonal effect is probably on the enzyme's milieu rather than on its synthesis by RNA or induction by DNA.
TL;DR: The most likely explanation for the defect in X-linked agammaglobulinaemias is either a regulatory gene controlling synthesis of light and heavy chains or a gene affecting the capacity of lymphocytes to differentiate into plasma cells.
Abstract: BOTH congenital and acquired idiopathic agammaglobulinaemias are genetically determined1. Congenital and some forms of acquired agammaglobulinaemias are X-linked. Studies of the mode of inheritance of various gamma globulin light and heavy chain allotypes in humans, rabbits and mice, however, have shown that the gene loci controlling those markers are autosomally inherited2. Thus the most likely explanation for the defect in X-linked agammaglobulinaemias is either a regulatory gene controlling synthesis of light and heavy chains or a gene affecting the capacity of lymphocytes to differentiate into plasma cells.
TL;DR: A case of the uqusual sex chromo some mosaicism 47XYY, @8XXYY, 49XXXYY in a subnormal man aged 22, who was discovered in a study of outstandingly tall in-patients in a hospital for the mentally subnormal.
Abstract: I wish to report a case of the uqusual sex chromo some mosaicism 47XYY, @8XXYY, 49XXXYY in a subnormal man aged 22, who was discovered in a study of outstandingly tall in-patients in a hospital for the mentally subnormal. A Caucasian, he was an illegitimate child and no details of his parents are obtainable. He walked at 2 years and talked at 3 years and he attended an ordinary school to the age of 7 and a special school until he was 15. He has a history of indecent be haviour and fire-raising, and intermittently he has shown evidence of delusions and hallucinations. On the Wechsler Adult Intelligence Scale his full scale intelligence quotient is 53. He is tall, height :82 cm., (73 inches), weight 6o kg. (:32 lb.). His head appears small, with a cranial circumference of 52 cm. He is of asthenic physique, with small testes, gynaecomastia and scanty pubic and axillary hair. His skull X-ray shows a bulky mandible and prominent supra orbital ridges. The pituitary fossa is normal. Electro encephalography shows no abnormality. His excretion of : 7 ketosteroids is i mg./24 hours and excretion of I 7 hydroxycorticosteroids less than : mg./24 hours (normal ranges, I 7 ketosteroids 5—28mg./24 hours,
TL;DR: There is good evidence for a suppression effect (2 to 4%) by the autosomal component in the ebony strain of Drosophila melanogaster, but no effect was found for the two Y chromosomes tested.
Abstract: Males from an ebony strain of Drosophila melanogaster show a consistent and deviant sex ratio in their progenies (53 to 57% females). The cause is a major gene on the X chromosome at approximately 48. Zygotic mortality is not the cause; therefore, a prezygotic mechanism is probably responsible. There is good evidence for a suppression effect (2 to 4%) by the autosomal component in the ebony strain. No effect was found for the two Y chromosomes tested.