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Location of Satellite and Homogeneous DNA Sequences on Human Chromosomes 总被引:15,自引:0,他引:15
HUMAN DNA1,2 contains at least two satellite fractions—satellite I (0.5% of the genome) which bands at a density of 1.687 g/cm3 in neutral CsCl and satellite II (2% of the genome) which bands at 1.693 g/cm3. The main band DNA has an average buoyant density between 1.670 and 1.720 g/cm3 and a light shoulder (constituting 15% of the genome) with a buoyant density of 1.696 g/cm3, referred to as homogeneous mainband. Satellite DNA has been observed in many higher organisms3, usually with an unknown function, notable exceptions being cistrons coding for ribosomal RNA4 and the DNA coding for histone messenger RNA5. To investigate possible functions of human repetitive DNA we have studied the annealing of complementary RNA fractions to chromosomes using in situ hybridization6,7. We describe here preliminary observations using human satellite II and homogeneous mainband fractions. 相似文献
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Ornjira Prakhongcheep Yuriko Hirai Toru Hara Kornsorn Srikulnath Hirohisa Hirai Akihiko Koga 《DNA research》2013,20(3):235-240
Alpha satellite DNA is a repetitive sequence known to be a major DNA component of centromeres in primates (order Primates). New World monkeys form one major taxon (parvorder Platyrrhini) of primates, and their alpha satellite DNA is known to comprise repeat units of around 340 bp. In one species (Azara''s owl monkey Aotus azarae) of this taxon, we identified two types of alpha satellite DNA consisting of 185- and 344-bp repeat units that we designated as OwlAlp1 and OwlAlp2, respectively. OwlAlp2 exhibits similarity throughout its entire sequence to the alpha satellite DNA of other New World monkeys. The chromosomal locations of the two types of sequence are markedly distinct: OwlAlp1 was observed at the centromeric constrictions, whereas OwlAlp2 was found in the pericentric regions. From these results, we inferred that OwlAlp1 was derived from OwlAlp2 and rapidly replaced OwlAlp2 as the principal alpha satellite DNA on a short time scale at the speciation level. A less likely alternative explanation is also discussed. 相似文献
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O. V. Muravenko E. D. Badaeva A. V. Amosova N. G. Shostak K. V. Popov A. V. Zelenin 《Russian Journal of Genetics》2001,37(12):1452-1454
To estimate the possibility of plant genome mapping using human genome probes, the probes fluorescent in situ hybridization (FISH) of human 18S–28S rDNA (clon 22F9 from the LA-13NCO1 library) was carried out on chromosomes of the spring barleyHordeum vulgareL. As a control, wheat rDNA probe (clon pTa71) was taken. Hybridization of the wheat DNA probe revealed two major labelling sites on mitotic barley chromosomes 5I (7H) and 6I (6H), as well as several minor sites. With the human DNA probe, signals were detected in the major sites of the ribosomal genes on chromosomes 5I (7H) and 6I (6H) only when the chromosome preparations were obtained using an optimized technique with obligatory pepsin treatment followed by hybridization. Thus, this study demonstrates that physical mapping of plant chromosomes with human DNA probes that are 60 to 70% homologous to the plant genes is possible. It suggests principal opportunity for the FISH mapping of plant genomes using probes from human genome libraries, obtained in the course of the total sequencing of the human genomes and corresponding to the coding regions of genes with known functions. 相似文献
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Banding Pattern of Human Chromosomes 总被引:1,自引:0,他引:1
W. SCHNEDL 《Nature: New biology》1971,233(37):93-94
STUDIES of mammalian chromosomes have advanced rapidly since the introduction of the quinacrine fluorescence technique1 and other procedures which are believed to locate repetitive DNA sequences in cytological chromosome preparations2,3. To improve these techniques, a method has been developed which can provide further information about chromosome organization. 相似文献
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Using C-banded preparations of Mus dunni it is possible to study the behavior of constitutive heterochromatin in early stages of meiotic prophase. The X and the Y chromosomes, both of which contain a large amount of heterochromatin, lie apart in leptotene but move toward each other during zygotene. They then form the sex vesicle at late zygotene. In autosomes zygotene pairing appears to start from the telomeric ends. The centromere of the Y chromosome associates end-to-end with the terminal end of the long arm of the X chromosome. The autosomal heterochromatic short arms show forked morphology in certain bivalents at pachytene, suggesting probable incomplete synapsis. 相似文献
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J. E. K. Cooper 《Chromosoma》1977,62(3):269-278
Newborn Microtus agrestis were given single acute whole-body -irradiation (350, 500, or 750R). C-banded bone marrow preparations showed cells with radiation-induced rearrangements of constitutive heterochromatin of the sex chromosomes, usually the consequence of single events, encompassing a wide spectrum of deletions and translocations. These cells persisted in bone marrow for more than a year after irradiation; however, many cells showing the same redistribution of heterochromatin constituted clones of both deletions and translocations. These results indicate that deletion or rearrangement of constitutive heterochromatin does not impair the capacity of bone marrow cells for further proliferation. 相似文献
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Slides pretreated for C-banding and stained with DAPI or CMA3 show different banding patterns in human metaphase chromosomes compared to those obtained with either standard Giemsa C-banding or fluorochrome staining alone. Human chromosomes show C-plus DA-DAPI banding after C-banding plus DAPI and enhanced R-banding after C-banding plus Chromomycin A3 staining. If C-banding preferentially removes certain classes of DNA and proteins from different chromosome domains, C-banding pre-treatment may cause a differential DNA extraction from G- and R-bands in human chromosomes, resulting in a preferential extraction of DNA included in G-bands. This hypothesis is partially supported by the selective cleavage and removal of DNA from R-bands of restriction endonuclease HaeIII with C-banding combined with DAPI or Chromomycin A3 staining. Structural factors relating to regional differences in DNA and/or proteins could also explain these results. 相似文献
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Banding in Human Chromosomes treated with Trypsin 总被引:23,自引:0,他引:23
THE differential staining properties of the Giemsa stain were first observed by Pardue and Gall1. They were studying in situ hybridization between mouse satellite DNA and mouse chromosomes and observed that following certain pretreatment the centromeric regions of mouse chromosomes were more densely stained by Giemsa stain than other regions. The darkly stained regions were considered to consist of constitutive heterochromatin. Similar observations were later made on human chromosomes by Arrighi and Hsu2 and Gagné et al.3. Through modifications of the original methods used in the DNA hybridization work, techniques have been developed which make each chromosome identifiable4–6. 相似文献
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Functional Complementation of a Genetic Deficiency with Human Artificial Chromosomes 总被引:7,自引:0,他引:7
José E. Mejía Adrian Willmott Elaine Levy William C. Earnshaw Zoia Larin 《American journal of human genetics》2001,69(2):315-326
We have shown functional complementation of a genetic deficiency in human cultured cells, using artificial chromosomes derived from cloned human genomic fragments. A 404-kb human-artificial-chromosome (HAC) vector, consisting of 220 kb of alphoid DNA from the centromere of chromosome 17, human telomeres, and the hypoxanthine guanine phosphoribosyltransferase (HPRT) genomic locus, was transferred to HPRT-deficient HT1080 fibrosarcoma cells. We generated several cell lines with low-copy-number, megabase-sized HACs containing a functional centromere and one or possibly several copies of the HPRT1 gene complementing the metabolic deficiency. The HACs consisted of alternating alphoid and nonalphoid DNA segments derived only from the input DNA (within the sensitivity limits of FISH detection), and the largest continuous alphoid segment was 158-250 kb. The study of both the structure and mitotic stability of these HACs offers insights into the mechanisms of centromere formation in synthetic chromosomes and will further the development of this human-gene-transfer technology. 相似文献
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正In the field of anthropology,the uniparentally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between males and females,with additional advantages of small effective population size,sufficient markers,and population-specific haplotype distribution(Jobling and Tyler-Smith,1995;Jin and Su,2000;Underhill et al.,2000).Many such population studies have rested on the 相似文献