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排序方式: 共有263条查询结果,搜索用时 15 毫秒
1.
Amplification of human minisatellites by the polymerase chain reaction: towards DNA fingerprinting of single cells. 总被引:59,自引:23,他引:36
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Hypervariable minisatellites can be amplified from human DNA by the polymerase chain reaction, using primers from DNA flanking the minisatellite to amplify the entire block of tandem repeat units. Minisatellite alleles up to 5-10 kb long can be faithfully amplified. At least six minisatellite loci can be co-amplified from the same DNA sample and simultaneously detected to provide a reproducible and highly variable DNA fingerprint which can be obtained from nanogram quantities of human DNA. The polymerase chain reaction can also be used to analyse single target minisatellite molecules and single human cells, despite the appearance of spurious PCR products from some hypervariable loci. DNA fingerprinting at the level of one or a few cells therefore appears possible. 相似文献
2.
Clustering of hypervariable minisatellites in the proterminal regions of human autosomes 总被引:42,自引:0,他引:42
Six of the human minisatellites detected by DNA fingerprint probes have been localized by in situ hybridization to human metaphase chromosomes. These hypervariable loci are not dispersed at random in the human genome, but show preferential, though not exclusive, localization to terminal G-bands of human autosomes. Two of the proterminal minisatellites are very closely linked to other variable loci. Sequence analysis of one of these additional minisatellites suggests that the two linked minisatellites arose by independent amplification of different repeat units. The proterminal regions of human autosomes may therefore be rich in minisatellites, analogous to the pseudoautosomal terminal pairing region of human sex chromosomes that is similarly abundant in hypervariable minisatellites. 相似文献
3.
R. J. Bellamy C. F. Inglehearn I. K. Jalili A. J. Jeffreys S. S. Bhattacharya 《Human genetics》1991,87(3):341-347
Summary We have compared band sharing between the DNA fingerprints of members of an inbred human population with band sharing between members of an outbred population. It had not previously been determined whether the high rate of mutation at minisatellite loci is sufficient to prevent an increase in band sharing in moderately inbred populations. We have found that there is an increase in band sharing in the 2-kb to 9-kb size range, but not in the >9-kb size range, in the inbred population. The difference was consistently observed using four different multi-locus probes, viz. 33.6, 33.15, (CAC)5 and M13. Thus, we have demonstrated that moderate but prolonged inbreeding can lead to increased similarity in human DNA fingerprints. This should be considered when analysing DNA fingerprints in forensic or paternity cases involving members of an inbred community. 相似文献
4.
5.
A Collick J Drew J Penberth P Bois J Luckett F Scaerou A Jeffreys W Reik 《The EMBO journal》1996,15(5):1163-1171
Various sequences in the mammalian genomes are unstable. One class of sequence arrangement is long inverted repeats, which are known to be unstable in bacteria and yeast. While in mammals some evidence suggests that short inverted repeats (<10 bp long) may show instability, nothing is known about the stability of long inverted repeats. Here we describe two unrelated multicopy transgenes in the mouse (loci 109 and OX1-5), each of which contains a long inverted repeat that shows substantial mitotic instability. This instability also occurs in the germline so that mutant transgenes appear within pedigrees at a high frequency. The mutation processes acting at these two inverted repeats are complex and can involve insertion or deletion, and can result in stabilization of the transgene. At transgene 109 mutational events range from very small rearrangements at the centre of the inverted repeat to complete transgene deletion. In addition we show that the rates of mutation at the inverted repeat of transgene OX1-5 can vary between the male and female germlines and between inbred strains of mice, suggesting the possibility of a genetic analysis to identify loci that modulate inverted repeat instability. 相似文献
6.
Minisatellite isoalleles can be distinguished by single-stranded conformational polymorphism analysis in agarose gels.
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Minisatellite isoallelism, i.e. the occurrence of minisatellite alleles with different internal sequence composition but indistinguishable length, is a common limitation of minisatellite allele length analysis. Internal sequence variation can be used to distinguish such isoalleles, provided that detailed sequence knowledge of its basis is available. We now show that minisatellite isoalleles can also be simply resolved by single-stranded conformational polymorphisms (SSCP) arising during agarose gel electrophoresis. SSCP on agarose gels can be used to distinguish minisatellite isoalleles either after PCR amplification, or by standard Southern blot analysis of genomic DNA. 相似文献
7.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
8.
9.
大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育 总被引:1,自引:0,他引:1
本实验用免疫组织化学ABC法研究了大鼠胼胝体内神经肽Y免疫反应阳性(NPY-IR)纤维的生后发育。结果发现,许多NPY-IR纤维在大鼠出生时便存在于胼胝体内。NPY-IR胼胝体纤维的密度在生后1周内继续逐渐增高,在第2周内达到最高峰。之后,NPY-IR胼胝体纤维的密度逐渐下降,至第3周末时接近成年时的水平,即仅有少量NPY-IR纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多NPY-IR胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。 相似文献
10.
The isolation and characterization of chloramphenicol resistant derivatives of the human cell line HeLa B is described. Growth of resistant lines was unaffected in the presence of 100 μg/ml
-threo-chloramphenicol, whereas growth of the parental cells was inhibited at 12.5 μg/ml. The incorporation of [35S]methionine into mitochondrial protein of intact resistant cells continued normally in the presence of 100 μg/ml chloramphenicol (cytoplasmic protein synthesis was blocked by addition of 50 μg/ml emetine). Under these conditions the electrophoretic profile of labelled, presumptive mitochondrially-made proteins was similar to that of the parental cell line labelled in the absence of chloramphenicol. The cell lines selected in the presence of chloramphenicol also showed increased resistance to some other inhibitors of mitochondrial protein synthesis, e.g. carbomycin and mikamycin. [14C]Chloramphenicol was found to have normal access to the interior of resistant cells and it is therefore unlikely that resistance results from altered cell permeability. No modification of the drug by acetylation or glucuronide conjugation mechanisms was observed. The possibilities remain that resistance is mediated by altered permeability of the mitochondrial membrane, or from modification to a component of the mitochondrial protein synthetic system. 相似文献