Showing papers on "Genome published in 1973"
TL;DR: The number of copies of viralDNA in DNA of cells transformed by adenovirus type 2 has been determined by following the kinetics of reassociation of 32P-labeled viral DNA in the presence of unlabeled DNA extracted from transformed and control cells.
263 citations
TL;DR: Through use of tetrad, random spore, trisomic, and mitotic analysis procedures a large number of genes, including 48 new genetic markers, were studied for their locations on the genetic maps of the yeast Saccharomyces cerevisiae, finding Functionally-related sets of genes generally were found to be dispersed over the genome.
Abstract: Through use of tetrad, random spore, trisomic, and mitotic analysis procedures a large number of genes, including 48 new genetic markers, were studied for their locations on the genetic maps of the yeast Saccharomyces cerevisiae. Eighteen new centromere linked genes were discovered and all but one was located on various ones of the 16 previously-established chromosomes. Five fragments of linked genes were also assigned to chromosomes; four were located on known chromosomes while the fifth determined one arm of a new chromosome. The experiments indicate that seventeen is likely to be the haploid chromosome number in this yeast. Most chromosomes have been established by genetic means to be metacentric and their genetic lengths vary from 5 cM to approximately 400 cM. Functionally-related sets of genes generally were found to be dispersed over the genome.
190 citations
TL;DR: DNA sequences complementary to RAV-O 60–70S RNA genome were detected and quantitated in DNA from normal avian embryos by the technique of RNA-DNA hybridization with DNA excess, providing additional firm support for the proposition thatnormal avian cells carry endogenous avian leukosis virus in the form of DNA proviruses.
120 citations
TL;DR: Using labelled double stranded (ds) DNA prepared in vitro with the reverse transcriptases of RNA tumour viruses, it is shown that this in vitro DNA probe did not effectively discriminate between the DNAs of different species with respect to the presence of viral genetic information.
Abstract: RNA type C viruses have been isolated from many animal species. In the mouse and chicken, they exist in an unexpressed form in every cell1–3. Whether endogenous type C viral genetic information is integrated within the cell genome has been studied genetically and biochemically. Loci for inducibility of biologically distinguishable viruses have been detected in mouse cells, suggesting that the loci may represent virus structural information4,5. Numerous biochemical studies have characterized and quantified type C virus-specific DNA in avian and murine cells6–9. In some reports, the number of viral DNA equivalents per cell was quantified by measuring the effect of unlabelled cellular DNA on the reassociation kinetics of a labelled DNA probe10. Using labelled double stranded (ds) DNA prepared in vitro with the reverse transcriptases of RNA tumour viruses, earlier reports indicated that the major portion of the type C virus ds DNA product was complementary to a relatively small fraction of the viral genome7,11; this in vitro DNA probe did not effectively discriminate between the DNAs of different species with respect to the presence of viral genetic information7,8. A portion of the ds DNA product was also shown to have a genetic complexity more representative of the 70S genome7,11.
90 citations
TL;DR: The discussion of the results of in situ hybridization experiments has shown that this technique opens a new dimension in cytological studies of chromosome structure and function in eukaryotes.
Abstract: Publisher Summary The techniques of DNA reassociation and molecular hybridization of single-stranded DNA with complementary RNA provide powerful tools for investigating questions on the molecular organization of the genomes of prokaryotes and eukaryotes, and on the nucleic acid metabolism of cells. The discussion of the results of in situ hybridization experiments has shown that this technique opens a new dimension in cytological studies of chromosome structure and function in eukaryotes. The combination of classic cytology with nucleic acid hybridization can be of fundamental benefit to the current attempts of molecular biology to make use of the vast amounts of classic cytological and cytogenetic knowledge in understanding genome organization and function in eukaryotes.
79 citations
TL;DR: If positive correlation exists between human phenotypes, it can be presumed that the genes are linked to the same chromosome (they are syntenic) and this provides strong support for the assignment of gene loci for particular phenotypes to particular human chromosomes.
Abstract: SOMATIC cell populations can be used for genetic analysis because of the occurrence of parasexual events1. Genetically dilferent genomes can combine into a single cell by spontaneous2 or virally induced3 cell fusion. In the interspecific hybrid combinations so far studied, the parental chromosomes are lost to a variable extent4. Human/mouse hybrids are particularly favourable for genetic analysis because they preferentially segregate the human chromosomes5. The mouse and human enzymes can be distinguished and the mouse and human chromosomes can be identified by the application of recently developed cytological techniques6,7. Linkage relationships can be inferred by the concordant or discordant segregation of human markers. If positive correlation exists between human phenotypes, it can be presumed that the genes are linked to the same chromosome (they are syntenic); and similarly, if positive correlations exist between chromosomes and phenotypes, this provides strong support for the assignment of gene loci for particular phenotypes to particular human chromosomes.
76 citations
TL;DR: The question of whether DNA sequences which specify protein structure are reiterated are still open and a special mechanism has been proposed to overcome this difficulty.
Abstract: BECAUSE of the large DNA content of the eukaryotic genome1,2 and the existence of reiterated DNA sequences3,4, it has been thought that the DNA sequences which specify protein structure are present in many copies per genome. The idea is not immediately compatible with the simple dominance relationships which alleles at many genetic loci show. A special mechanism has been proposed to overcome this difficulty5, which can also be surmounted in many other ways. From a theoretical standpoint, the question of whether DNA sequences which specify protein structure are reiterated is still open.
72 citations
TL;DR: Genetic analyses demonstrate the segregation of three targets for the K restriction system in h80iλ hybrid phages: sk-1 and sk-2 are located on the λ genome, and the third target is in the phi80 genome right of, but close to, att.
Abstract: Genetic analyses demonstrate the segregation of three targets for the K restriction system in h80iλ hybrid phages Mutations in each of these three targets have been isolated and shown to confer resistance in cis but not in trans Two of the three targets (sk-1 and sk-2) have been located on the λ genome: sk-1 is right of gene R and sk-2 is between genes cIII and N The third target is in the phi80 genome right of, but close to, att Phage λ lacking both sk-1 and sk-2 retains at least 3 targets for the K restriction system
71 citations
TL;DR: The data suggest that evolution by polyploidy may be more common in crustaceans than earlier data had indicated and recommend the Crustacea for further studies in evolutionary genetics.
Abstract: Nuclear DNA amounts have been determined for 42 species of crustaceans bringing the total number of species with known nuclear DNA content to over 70. Genome size in Crustacea varies over a 25-fold range with a modal value of 2 to 3 pg haploid being common in many groups. Both average genome size and the amount of variability among species are characteristic for certain groups. A trend towards small genomes is evident in advanced and specialized crustacean groups. Somatic polyploidy is a very pronounced feature of the Crustacea. The data suggest that evolution by polyploidy may be more common in crustaceans than earlier data had indicated. These features and the presence of very characteristic satellite fractions in the nuclear DNA recommend the Crustacea for further studies in evolutionary genetics.
60 citations
TL;DR: By isolating bluetongue virus single-stranded RNA from polyribosome complexes in the cell, it is shown that the relative molar ratios in which the mRNA species become attached to the ribosomes is similar to the ratio in which they are synthesized.
57 citations
TL;DR: It is concluded that the data assign a feline origin rather than a human origin to RD-114, which provides a method for determining the taxonomic position of the natural host of any new RNA tumor virus isolated.
Abstract: The lysogenic bacteriophages and the RNA tumor viruses have in common the ability to add their genetic information to the genome of their host cells. The biological similarity extends further; data summarized here indicate that they both possess homology to the DNA of their uninfected indigenous hosts. Sharing of common sequences with normal host DNA has been established with avian, murine, feline, and primate oncornaviruses. This finding provides a method for determining the taxonomic position of the natural host of any new RNA tumor virus isolated. Application of this approach to RD-114 revealed extensive hybridization to normal cat DNA and little, if any, hybridization to human DNA. We conclude that the data assign a feline origin rather than a human origin to RD-114.
TL;DR: There does appear to be a general decrease in the percentage usage of ribosomal and transfer RNA genes as a mammalian species' aging rate decreases, and the results are discussed with respect to a unified theory of aging for mammalian species.
TL;DR: This work proposes a structure for the genome of Drosophila melanogaster in which each chromatid of each chromomere (band) consists of about 30-35 different sequences of single-copy (unique) DNA, each on the average about 750 base pairs in length.
Abstract: We propose a structure for the genome of Drosophila melanogaster in which each chromatid of each chromomere (band) consists on the average of about 30-35 different sequences of single-copy (unique) DNA, each on the average about 750 base pairs in length. These are separated from one another by stretches of the middle repetitive (reiterated) DNA, which in D. melanogaster makes up about 15% of the genome. These stretches are about 100-150 base pairs in length and are all of the same sequence or family in each individual chromomere and of a different family (sequence) in each different chromomere. Our proposed structure of the Drosophila genome is in accord with all of the known facts concerning the physical chemistry and molecular biology of Drosophila DNA.
TL;DR: It is thought that even if hybridization and autoradiographic efficiencies were 100%, then at most only 6 × 10−6 silver grains would have been produced over the diploid cell's haemoglobin loci.
Abstract: Price, Conover and Hirschhorn1 have reported the in situ hybridization of haemoglobin mRNA to diploid chromosomes. We think such a conclusion to be impossible because the specific activity of their mRNA was 6 × 10−7 disintegrations per mRNA molecule during the two week exposure of their autoradiographs. As a genome has been reported to contain less than five haemoglobin cistrons2, even if hybridization and autoradiographic efficiencies were 100%, then at most only 6 × 10−6 silver grains would have been produced over the diploid cell's haemoglobin loci.
TL;DR: Somatic cell hybrids of Burkitt lymphoblastoid cells, from which Epstein-Barr virus can be recovered, were examined for the presence of virus DNA by DNA-RNA hybridization.
Abstract: Somatic cell hybrids of Burkitt lymphoblastoid cells, from which Epstein-Barr virus can be recovered, were examined for the presence of virus DNA by DNA-RNA hybridization. Four clones of hybrid cells, each negative for virus antigens by immunofluorescence, contained virus DNA in varying genomic equivalents. The number of virus genome equivalents increased in the hybrid cells after induction of virus with iododeoxyuridine.
DOI•
01 Jan 1973TL;DR: Drosophila Melanogaster has only four chromosome pairs, its formal genetics is better known than that of any other eukaryote, and cytological analysis is facilitated by the existence of the giant polytene chromosomes in larval salivary glands.
Abstract: Among the higher eukaryotes, Drosophila Melanogaster has one of the smallest reported genome sizes. According to the spectrophotometric data of Rasch et al. (1971) the haploid DNA content is 1.8 × 10−13g, corresponding to 1.1 X 1011 daltons or approximately 40 times the genome size of E. Coli. For this reason alone, analysis of the organization of DNA in Drosophila should be easier than in organisms with larger amounts of DNA in the haploid chromosome set. Furthermore, D. Melanogaster has only four chromosome pairs, its formal genetics is better known than that of any other eukaryote, and cytological analysis is facilitated by the existence of the giant polytene chromosomes in larval salivary glands.
TL;DR: The finding that in most transformed cell lines only a fraction of the viral genome is transcribed and only non-structural virus specific antigens can be detected in all transformed cells suggests that non-Structural virus gene products are involved in transformation.
Abstract: STABLE transformation occurs in cells in which the simian virus 40 (SV40) genome is permanently established1,2. The expression of only a part of the viral genome seems sufficient to maintain the transformed state. This is supported by the finding that in most transformed cell lines only a fraction of the viral genome is transcribed3,4 and only non-structural virus specific antigens (U (ref. 5), Τ (ref. 6), TSTA (ref. 7)) can be detected in all transformed cells. The lack of detectable structural virus proteins suggests that non-structural virus gene products are involved in transformation. That the non-structural viral proteins represent only a minor fraction of the total proteins in transformed as well as in productively infected cells constitutes a major obstacle for their identification and characterization8.
TL;DR: The results support earlier findings that members of the genus Acholeplasma have genome sizes about twice those of the family Mycoplasma (family MyCoplasmataceae).
Abstract: SUMMARY: Within the order Mycoplasmatales guanine plus cytosine contents and genome sizes have been determined for 17 strains representing 15 bovine and two ovine species, subspecies or serogroups. The guanine plus cytosine contents were found to vary between 24.4 and 32.9%. The genome sizes were 4.0 to 5.6 × 108 daltons for 14 sterol-requiring strains and 0.99 to 1.1 × 109 daltons for three non-sterol-requiring strains. These results support earlier findings that members of the genus Acholeplasma (family Acholeplasmataceae) have genome sizes about twice those of the genus Mycoplasma (family Mycoplasmataceae).
TL;DR: DNA was isolated from highly purified symbiont lambda particles of Paramecium aurelia andRenaturation kinetic data revealed a molecular size of 0.71 × 10 9 daltons, which correspond to about ten copies of the genome per lambda particle.
DOI•
01 Jan 1973
TL;DR: In phage genetics, the most extensively investigated mechanism of abortive infection by wild-type viruses is that of DNA restriction: the injected viral DNA is cut to pieces by the action of nucleotide sequence-specific restriction enzymes of the host.
Abstract: A viral genome codes for only part of the genetic information necessary for its self-replication. The host contributes the machinery for energy production, the building blocks of viral nucleic acids and proteins, and a transcription-translation apparatus. Despite the universality of the genetic code and of basic metabolic pathways, however, a wild-type viral genome that succeeds in invading a given, normally metabolizing host cell may possibly not yield progeny: for normal virus growth, the viral genome apparently has to be in tune with the genome of the host in regard to factors that are highly specific for a given virus. In addition to examples of such situations in animal virology (Dulbecco, 1969; Bang, 1972), several phage-bacteria systems are known in which virus infection is abortive, or results in a low yield of progeny virus. In phage genetics, the most extensively investigated mechanism of abortive infection by wild-type viruses is that of DNA restriction: the injected viral DNA is cut to pieces by the action of nucleotide sequence-specific restriction enzymes of the host (see review: Meselson et al., 1972). The physical destruction of the invading phage genome is an efficient, straightforward way of interfering with the normal course of viral development. However, several other examples of abortive infection by wild-type phages are known, in which interference with the physical integrity of the invading genome does not seem to be the cause for failure of phage growth (Hausmann et al., 1968; Morrison and Malamy, 1971; Georgopoulos, 1971; Moyer et al., 1972). In such cases, at what stages of viral development and by which mechanisms does the block occur?
TL;DR: Strand selection during the transcription of the genome of human adenovirus 2 was studied by DNA · RNA hybridization and Transcripts from both H and L strands were detected both early and late after productive infection of human KB cells.
TL;DR: The stimulation of in vitro tRNA aminoacylation by post-microsomal supernatant enzymes isolated from Abnormal Abdomen adult flies is a function of the residual genome of these flies rather than of the major mutant gene, A 53 g.
Abstract: The stimulation of in vitro tRNA aminoacylation by post-microsomal supernatant enzymes isolated from Abnormal Abdomen ( A 53 g ) adult flies is a function of the residual genome of these flies rather than of the major mutant gene, A 53 g . Genes controlling this stimulation are located on the X chromosome as well as on the autosomes. These observations are discussed in terms of the phenotypic effect of the major mutant gene in response to changes in protein synthesis which are under the control of modifier genes responsible for aberrant genetic translation mechanisms.
TL;DR: Results indicate that the decay of incorporated (32)P leads to damages that prevent the efficient transfer of portions of the genome distal to the lesion and that single-strand breaks have little or no effect on the transfer of the bacteriophage SP82G genome.
Abstract: The last genetic markers to be transferred during bacteriophage SP82G infection have a higher sensitivity to the decay of incorporated radioactive phosphorous ((32)P) than those which are located on the proximal end of the genome. If (32)P decay is permitted to take place after DNA transfer is complete (in frozen infective centers) and in the absence of DNA replication, no dependence of marker sensitivity on map position is observed. These results indicate that the decay of incorporated (32)P leads to damages that prevent the efficient transfer of portions of the genome distal to the lesion. At 4 C, failure to transfer some portion of the genome occurs in 49% of all lethal events. Even though damages that prevent transfer of the genome are in themselves lethal, they do not prevent rescue of genetic markers on portions of the genome that are transferred. The portion of the genome that is transferred, is transferred at the same rate as an undamaged genome. We interpret these results to mean that double-strand breaks in the DNA are the lesions that prevent distal transfer and that single-strand breaks have little or no effect on the transfer of the bacteriophage SP82G genome.
TL;DR: It was found that this parameter decreased with decreasing degree of glucosylation, and that the kinetic complexity of non-glucosylated DNA was in agreement with the known genome size of T4 phage.
TL;DR: Data obtained from photomicrographs of cells of plants from Alaska and Wyoming suggest that timothy has one genome in common with , and all indications are that is an autohexaploid, and is an allotetraploid.
Abstract: Two polyploid and one diploid timothy species are found in North America: L. (2n = 42), var. (Gaud.) Koch (2n = 28), and DC. (2n = 14). Karyotypes and photomicrographs of and Gaud. and a photomicrograph of are presented.Chromosome arm-length measurements, arm-length ratios, and other detailed observations showed that has three pairs of short acrocentric chromosomes, three pairs of long submetacentric chromosomes, and three pairs of equisized chromosomes with satellites. has two pairs of small acrocentric chromosomes, and one pair of long metacentrics, a slightly shorter pair of submetacentrics, and a pair of satellited chromosomes. This and other data obtained from photomicrographs of cells of plants from Alaska and Wyoming suggest that has one genome in common with . All indications are that is an autohexaploid, and is an allotetraploid. The genome is karyotypically similar to the genome.
TL;DR: End fragments of molecular weight 1 to 2.5 × 10 6 were prepared from the DNA molecules of human and simian adenovirus and shown by DNA-DNA hybridization to contain only 15 to 30% of the sequences present in the entire genome, eliminating the possibility that adenvirus DNA molecules are circularly permuted.