Showing papers on "Chromosome 22 published in 1972"
TL;DR: Hybridization of (3)H-labeled ribosomal RNA to human chromosomes on slides resulted in specific labeling of the satellite regions of chromosomes 13, 14, 15, 21, and 22, with an over-all efficiency of about 5%.
Abstract: Hybridization of 3H-labeled ribosomal RNA to human chromosomes on slides resulted in specific labeling of the satellite regions of chromosomes 13, 14, 15, 21, and 22, with an over-all efficiency of about 5%. Differences between D and G chromosomes, and between associated and unassociated satellites, were not significant. Labeling of all other parts of the preparations was nonspecific, and increased in the order: extrachromosomal regions < chromosome arms < centric regions.
515 citations
01 Jan 1972
TL;DR: Molecular genetics has given new insights into chromosomal structure and function, its mechanism of replication, the linear sequence of its repeating units which form the genetic code, and the process by which this code is transcribed into a specific protein structure.
Abstract: The concept that chromosomes are essential constituents of cells is nearly a hundred years old. Genetical studies have demonstrated that chromosomes are the carriers of the genes, which determine the hereditary characteristics of the organism. Molecular genetics has given new insights into chromosomal structure and function, its mechanism of replication, the linear sequence of its repeating units which form the genetic code, and the process by which this code is transcribed into a specific protein structure. The chromosomes and their genes are acknowledged to be the biological basis of human variation in health and disease.
114 citations
TL;DR: In this article, a translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the human C-11 chromosome.
Abstract: Independently derived man-mouse somatic cell hybrids and their derivative subclones show a positive correlation between the expression of human lactate dehydrogenase A subunits and the occurrence of the human C-11 chromosome. Data are also presented that confirm the previously reported linkage of the thymidine kinase locus to the E-17 chromosome. A translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the E-17 chromosome. This translocation also provides evidence for translocation between man and mouse chromosomes in somatic cell hybrids. A presumptive association between the human phenotype for isocitrate dehydrogenase and the human F group is also described. Identification of specific human chromosomes was achieved by the application of several new cytological techniques: measurement of chromosome arm length, in situ annealing with mouse satellite complementary RNA, constitutive heterochromatin staining with Giemsa, and quinacrine mustard fluorochromatic staining.
108 citations
TL;DR: It can be concluded that a deletion of a chromosome 22 is compatible with a normal phenotype and that the cat-eye syndrome results, at least in this family, from a partial trisomy 22.
Abstract: A family is presented in which a phenotypically normal mother and her healthy daughter both had abnormal children with a small supernumerary chromosome. Both had clinical symptoms suggestive of cat-eye syndrome. In both women 1 G-chromosome was found to be replaced by a small submetacentric satellited chromosome. Its fluorescence pattern was compatible with that of a chromosome 22, and so was the fluorescence pattern of the supernumerary chromosome in one of the phenotypically abnormal children. Since complete monosomy G in addition to partial autosomal trisomy would not be compatible with clinical “normality” the respective karyotypes must be interpreted as a small deletion of a chromosome 22 in the healthy mother and daughter and a partial trisomy 22 in their abnormal children. Therefore it can be concluded that a deletion of a chromosome 22 is compatible with a normal phenotype and that the cat-eye syndrome results, at least in this family, from a partial trisomy 22.
57 citations
TL;DR: It was shown that the ribosomal cistrons (rDNA) are located in the nucleolus organizing system (satellite, nucleolar constriction and organizer) of the satellited chromosome pairs I (S1) and V (S2), in the proximal heterochromatic segment of the long arm of chromosomes S1 and in the terminal heterochrome segment of chromosome pair II.
Abstract: Tritiated ribosomal RNA (rRNA) was prepared from hypocotyls of Phaseolus coccineus grown in liquid culture in the dark and in presence of 5-3H-uridine. A mixture of the 18S and 25S 3H-rRNA fractions was used for hybridization with DNA in the polytene chromosome cells of the embryo suspensor of P. coccineus. It was shown that the ribosomal cistrons (rDNA) are located in the nucleolus organizing system (satellite, nucleolar constriction and organizer) of the satellited chromosome pairs I (S1) and V (S2), in the proximal heterochromatic segment of the long arm of chromosomes S1 and in the terminal heterochromatic segment of chromosome pair II. The micronucleoli which are produced by the satellite and nucleolus organizer of the chromosome pair S1 contain rDNA; on the contrary, no rRNA-DNA hybridization is found in the DNA containing granules which are produced by the satellite and nucleolus organizer of chromosome pair S2. The DNA which is amplified during production of DNA puffs at some chromosomal regions apparently does not code for ribosomal RNA (no detectable rRNA-DNA hybridization).
53 citations
TL;DR: Several hybrid lines between human and mouse somatic cells, containing one or two complements of mouse chromosomes and a reduced complement of human chromosomes, have been examined for the presence of mouse and human mitochondrial DNAs.
Abstract: Several hybrid lines between human and mouse somatic cells, containing one or two complements of mouse chromosomes and a reduced complement of human chromosomes, have been examined for the presence of mouse and human mitochondrial DNAs. For this analysis, advantage was taken of the fact that these two types of mitochondrial DNA have a buoyant density difference in CsCl gradients of 0.008 g/cm3. In all the hybrid clones analyzed, which retained an average number of human chromosomes estimated conservatively to vary from 5 to 23, only mitochondrial DNA of mouse character was detected. It seems likely that either repression of relevant human genes by the mouse genome or loss of human chromosomes is responsible for these results. If the latter explanation is true, since chromosome loss under the conditions used here was substantially a random process, one would have to assume that the activity of nuclear genes distributed in many chromosomes is required for the survival of mitochondrial DNA.
44 citations
TL;DR: It was found that in all 3 mosaic cultures the 45,X cells had a faster cell cycle than the second cell population and it is argued that heterochromatin has a retardative effect on cell division.
Abstract: Fibroblasts were grown from skin explants of 3 human females who are sex chromosome mosaics. The 3 cultures had the following chromosome complements: 45,X/46,XX, 45,X/46,XXqi and 45,X/47,XXX. Using thymidine labelling and Colcemid accumulation of metaphases it was found that in all 3 mosaic cultures the 45,X cells had a faster cell cycle than the second cell population. The difference in cell cycle duration was attributed to the longer G1 phase in the cells with 2 or 3 X chromosomes. The 2 populations of cells in the mosaic only differ in the number of heterochromatic X chromosomes and it is argued that heterochromatin has a retardative effect on cell division.
38 citations
TL;DR: Meiotic studies of (T1Wh × T163H) F1 hybrids showed a chain quadrivalent at metaphase I, confirming that both translocations shared in common only chromosome 19, and frequent nondisjunction of the T1Wh and T 163H translocation chromosomes.
Abstract: Quinacrine-mustard staining and Giemsa-banding identified the large chromosome of the T1Wh translocations as No. 5; the small autosome of the translocation had previously been found to be No. 19. Others have demonstrated that translocation T163H involved autosomes 9 and 19; these findings were confirmed in our study. Meiotic studies of (T1Wh × T163H) F1 hybrids showed a chain quadrivalent at metaphase I, confirming that both translocations shared in common only chromosome 19. Metaphase II analysis of F1 hybrids demonstrated frequent nondisjunction of the T1Wh and T163H translocation chromosomes, and 12 % of 75 F2 offspring from 16 F1 crosses were trisomic for chromosome 19. Trisomics had three translocation chromosomes and a chromosome number of 38. All newborn trisomics were smaller than their normal littermates and died during the first day of life. The only specific malformation found so far has been cleft palate.
38 citations
TL;DR: The use of clones derived from a female mule1 typed for Gd and at the same passage labelled with 3H-TdR and subsequently autoradiographed should provide final proof of this relationship between late DNA replication and X chromosome inactivation.
Abstract: THE relationship between late DNA replication and X chromosome inactivation is supported by strong circumstantial evidence1–3. The use of clones derived from a female mule1 typed for Gd and at the same passage labelled with 3H-TdR and subsequently autoradiographed should provide final proof of this relationship.
27 citations
TL;DR: The autosome in Searle's X-autosome translocation has been shown to be chromosome 16 and available evidence indicates that either Linkage Group XV or linkage Group XIX is carried on chromosome 16.
Abstract: The autosome in Searle's X-autosome translocation has been shown to be chromosome 16. The breakpoint in chromosome 16 is slightly proximal to the middle and in the X is slightly distal to the middle.—Available evidence indicates that either Linkage Group XV or Linkage Group XIX is carried on chromosome 16.—The centromere of the X chromosome is at the spf end of the linkage group.
20 citations
TL;DR: In the present study chromosome numbers of 13 Trifolium species were determined, making a total of 155 species for which chromosome numbers have been reported.
Abstract: In the present study chromosome numbers of 13 Trifolium species were determined, making a total of 155 species for which chromosome numbers have been reported. Four species which have been reported...
TL;DR: In this article, an inverted segment in one of the chromosomes of Sordaria brevicollis has been found to have a marked effect on recombination within a gene in another chromosome.
Abstract: An inverted segment in one of the chromosomes of Sordaria brevicollis has been found to have a marked effect on recombination within a gene in another chromosome. There are two effects on the intragenic recombination pattern, namely, a change in the polarity of recombination and a change in the frequency of parental and recombinant outside markers. The results support the idea that a mechanism exists for cancelling crossovers shortly after they have been formed as a means of controlling their number.
TL;DR: Treatment with medium-chain triglycerides (MCTs) did not significantly alter the clinical state, the serum protein levels or protein loss measured by chromium 51, and more obvious improvement has followed dietary exclusion of cow's milk protein.
Abstract: (I) Protein-losing Enteropathy Hypoproteinmmic cedema was present since birth. Studies using chromium 51 demonstrated abnormal gastrointestinal protein loss. Jejunal biopsies revealed subtotal villous atrophy. Coeliac disease was excluded by the evidence of intestinal disease before any gluten ingestion. There was no evidence of intestinal lymphangiectasis. Treatment with medium-chain triglycerides (MCTs) did not significantly alter the clinical state, the serum protein levels (see Fig 1) or protein loss measured by chromium 51. More obvious improvement has followed dietary exclusion of cow's milk protein. Throughout both periods of treatment the diet contained no lactose.