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51.
Background
Pathway-targeted or low-density arrays are used more and more frequently in biomedical research, particularly those arrays that are based on quantitative real-time PCR. Typical QPCR arrays contain 96-1024 primer pairs or probes, and they bring with it the promise of being able to reliably measure differences in target levels without the need to establish absolute standard curves for each and every target. To achieve reliable quantification all primer pairs or array probes must perform with the same efficiency. 相似文献52.
Adega F Chaves R Guedes-Pinto H Heslop-Harrison JS 《Cytogenetic and genome research》2006,114(2):140-146
Repetitive DNA in the mammalian genome is a valuable record and marker for evolution, providing information about the order and driving forces related to evolutionary events. The evolutionarily young 1.709 satellite IV DNA family is present near the centromeres of many chromosomes in the Bovidae. Here, we isolated 1.709 satellite DNA sequences from five Bovidae species belonging to Bovini: Bos taurus (BTA, cattle), Bos indicus (BIN, zebu), Bubalus bubalis (BBU, water buffalo) and Tragelaphini tribes: Taurotragus oryx (TOR, eland) and Tragelaphus euryceros (TEU, bongo). Its presence in both tribes shows the sequence predates the evolutionary separation of the two tribes (more than 10 million years ago), and primary sequence shows increasing divergence with evolutionary distance. Genome organization (Southern hybridization) and physical distribution (in situ hybridization) revealed differences in the molecular organization of these satellite DNA sequences. The data suggest that the sequences on the sex chromosomes and the autosomes evolve as relatively independent groups, with the repetitive sequences suggesting that Bovini autosomes and the Tragelaphini sex chromosomes represent the more primitive chromosome forms. 相似文献
53.
Alkhimova OG Mazurok NA Potapova TA Zakian SM Heslop-Harrison JS Vershinin AV 《Chromosoma》2004,113(1):42-52
Although the monomer size, nucleotide sequence, abundance and species distribution of tandemly organized DNA families are well characterized, little is known about the internal structure of tandem arrays, including total arrays size and the pattern of monomers distribution. Using our rye specific probes, pSc200 and pSc250, we addressed these issues for telomere associated rye heterochromatin where these families are very abundant. Fluorescence in situ hybridization (FISH) on meiotic chromosomes revealed a specific mosaic arrangement of domains for each chromosome arm where either pSc200 or pSc250 predominates without any obvious tendency in order and size of domains. DNA of rye-wheat monosomic additions studied by pulse field gel electrophoresis produced a unique overall blot hybridization display for each of the rye chromosomes. The FISH signals on DNA fibres showed multiple monomer arrangement patterns of both repetitive families as well as of the Arabidopsis-type telomere repeat. The majority of the arrays consisted of the monomers of both families in different patterns separated by spacers. The primary structure of some spacer sequences revealed scrambled regions of similarity to various known repetitive elements. This level of complexity in the long-range organization of tandem arrays has not been previously reported for any plant species. The various patterns of internal structure of the tandem arrays are likely to have resulted from evolutionary interplay, array homogenization and the generation of heterogeneity mediated by double-strand breaks and associated repair mechanisms. 相似文献
54.
55.
LINEs and gypsy-like retrotransposons in Hordeum species 总被引:3,自引:0,他引:3
56.
Chaves R Adega F Santos S Guedes-Pinto H Heslop-Harrison JS 《Cytogenetic and genome research》2002,96(1-4):113-116
Chromosome banding is often required in conjunction with fluorescent in situ hybridization of labelled probes for chromosome painting, satellite DNA and low-copy sequences to allow identification of chromosomes and simultaneous probe localization. Here, we present a method that reveals both patterns with only one observation step. The band pattern is produced by restriction-enzyme digestion of chromosomes, followed by fixation with paraformaldehyde in PBS, a short chromosome denaturation step in hybridization solution, and then standard in situ hybridization, washing and detection protocols. Using a range of different mammalian species, chromosome-banding patterns were immediately recognizable, although synchronisation procedures normally required for high- resolution G-banding were not needed. Unlike other methods available, only one round of observation is required using a conventional fluorescence microscope, the method works without modification in many species, and in situ hybridization is not used for chromosome identification (allowing multiple targets and minimizing background). The banding pattern is probably generated by a combination of DNA dissolution and heterochromatin reorganisation after enzyme digestion, followed by paraformaldehyde fixation of the new chromatin structure and incomplete denaturation. The method is of widespread utility in comparative genomics and genome organization programmes. 相似文献
57.
Comparative analysis of the zeta-crystallin/quinone reductase gene in guinea pig and mouse 总被引:1,自引:0,他引:1
Gonzalez P; Hernandez-Calzadilla C; Rao PV; Rodriguez IR; Zigler JS Jr; Borras T 《Molecular biology and evolution》1994,11(2):305-315
zeta-Crystallin is a novel nicotinamide adenine dinucleotide
phosphate:quinone reductase, present at enzymatic levels in various tissues
of different species, which is highly expressed in the lens of some
hystricomorph rodents and camelids. We report here the complementary DNA
(cDNA) cloning of zeta-crystallin from liver libraries in guinea pig (Cavia
porcellus), where zeta-crystallin is highly expressed in the lens, and in
the laboratory mouse (Mus musculus), where expression in the lens occurs
only at enzymatic levels. A 5' untranslated sequence different from the one
previously reported for the guinea pig lens cDNA was found in these clones.
We also report the isolation of genomic clones including the complete
guinea pig zeta-crystallin gene and the 5' region of this gene in mouse.
These results show the presence of two promoters in the guinea pig
zeta-crystallin gene, one responsible for expression at enzymatic levels
and the other responsible for the high expression in the lens. The guinea
pig lens promoter is not present in the mouse gene. This is the first
example in which the recruitment of an enzyme as a lens crystallin can be
explained by the acquisition of an alternative lens- specific promoter.
相似文献
58.
Comparative physical mapping of the 5S and 18S-25S rDNA in nine wild Hordeum species and cytotypes 总被引:8,自引:0,他引:8
S. Taketa G. E. Harrison J. S. Heslop-Harrison 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(1):1-9
Absract The physical locations of the 5S and 18S-25S rDNA sequences were examined in nine wild Hordeum species and cytotypes by double-target in situ hybridization using digoxigenin-labelled 5S rDNA and biotin-labelled 18S-25S
rDNA as probes. H. vulgare ssp. spontaneum (2n=2x=14; I-genome) had a similar composition of 5S and 18S-25S rDNA to cultivated barley (H. vulgare ssp. vulgare, I-genome), with two major 18S-25S rDNA sites and minor sites on four of the other five chromosomes; three chromosomes had
5S rDNA sites. The closely related H. bulbosum (2x; also I-genome) showed only one pair of 5S rDNA sites and one pair of 18S-25S rDNA sites on different chromosomes. Four wild
diploid species, H. marinum (X-genome), H. glaucum and H. murinum (Y-genomes) and H. chilense (H-genome), differed in the number (2–3 pairs), location, and relative order of 5S and the one or two major 18S-25S rDNA
sites, but no minor 18S-25S rDNA sites were observed. H. murinum 4x had three chromosome pairs carrying 5S rDNA, while the diploid had only a single pair. Two other tetraploid species, H. brachyantherum 4x and H. brevisubulatum 4x (both considered to have H-type genomes), had minor 18S-25S rDNA sites, as well as the major sites. Unusual double 5S rDNA
sites – two sites on one chromosome arm separated by a short distance – were found in the American H-genome species, H. chilense and H. brachyantherum 4x. The results indicate that the species H. brachyantherum 4x and H. brevisubulatum 4x have a complex evolutionary history, probably involving the multiplication of minor rDNA sites (as in H. vulgare sensu lato), or the incorporation of both I and H types of genome. The rDNA markers are useful for an investigation of chromosome evolution
and phylogeny.
Received: 9 February 1998 / Accepted: 14 July 1998 相似文献
59.
60.