ISSN:0173-0835    

DOI:10.1002/elps.1150180902

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractMinisatellites provide not only the basis for DNA fingerprinting and DNA profiling but also extremely informative systems for analysing processes of tandem repeat turnover in the human genome. Minisatellite instability appears to involve distinct mutation processes in somatic and germline cells; in the germline, mutation is frequently dominated by inter‐allelic conversion‐like events most likely occurring at meiosis and apparently regulated bycis‐acting mutation initiator elements. Attempts to define these initiators in transgenic mice have so far been thwarted by what appears to be a major human/mouse barrier to the inter‐species transfer of repeat instability. Minisatellites not only show high frequency spontaneous mutation in the germline, but also appear to be very sensitive to mutation induction by ionizing radiation, both in experimentally irradiated mice and in human populations exposed following the Chernobyl disaster; the mechanisms of mutation induction by radiation remain en

ISSN:0173-0835    

DOI:10.1002/elps.1150180903

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractThe reproducibility and potential applications of anonymous amplification protocols can be improved by using pairs of primers, each of 18 to 24 bases, to replace the single 8 to 10 base primers normally used in randomly amplified polymorphic DNA (RAPD) or DNA amplification fingerprinting (DAF) methods. Amplification using large primer pairs (LP‐RAPD) generates 5 to 30 bands that can be resolved on standard agarose gels. Complex fingerprints can be readily generated from viruses, bacteria, fungi, plants, invertebrates and vertebrates. We also present evidence that a number of polymerase chain reaction (PCR) methods, including those based on the use of enterobacterial repetitive intergenic consensus (ERIC‐PCR) or microsatellite primed (MP‐PCR) sequence, may in essence operate by the same mechanism as LP‐RAPD. Using standard LP‐RAPD protocols, reproducible fingerprints can be generated from a single specimen using different thermocyclers, regardless of the mechanism used for thermocycling (air‐cooled, Peltier effect, or robotic arm). LP‐RAPD is sensitive to intraspecific and interspecific genetic variation, demonstrated here by analysis of mites and apple cultivars. Approximately 50% of LP‐RAPD products are expected to have different primers at either end. Polymorphic bands with this arrangement can be recovered from the gel and directly sequenced using the LP‐RAPD primers themselves. The efficiency of sequencing is improved by the length of the LP‐RAPD primers. This method has the potential to allow the production of allele‐specific species markers

ISSN:0173-0835    

DOI:10.1002/elps.1150180904

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractA rapid approach for isolation of microsatellites and other tandem repeated sequences in described. The method is based on hybridization capture of repetitive elements from digested genomic DNA using biotinylated oligonucleotide probes in solution and subsequent attachment to magnetic beads coated with streptavidin. Captured fragments are amplified by adapter polymerase chain reaction (PCR) and the PCR products enriched for microsatellites cloned directly into a T‐vector for sequencing. The results presented here show that this approach is highly effective, allowing di‐ and trinucleotide repeats to be isolated and sequenced directly from fish and mammalian genomic DNA within four to five days. Assuming a density and relative abundance of repeats with AC/GT motifs corresponding to that found in the human genome, the protocol presented gives at least a 35‐fold enrichment of AC/GT microsatellites using an (AC)10oligo probe. In addition, four out of five sequences captured by a (CAG)9oligo probe contained one or several CAG repeat arrays. The efficiency of this direct approach suggests that it can be used for extracting other types of tandem and interspersed repeated sequences (including transposons, rRNA and tRNA genes and proviruses) from vertebrate ge

ISSN:0173-0835    

DOI:10.1002/elps.1150180905

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractMicrosatellites or simple sequence repeats (SSRs) are ubiquitous in eukaryotic genomes. Single‐locus SSR markers have been developed for a number of species, although there is a major bottleneck in developing SSR markers whereby flanking sequences must be known to design 5′‐anchors for polymerase chain reaction (PCR) primers. Inter SSR (ISSR) fingerprinting was developed such that no sequence knowledge was required. Primers based on a repeat sequence, such as (CA)n, can be made with a degenerate 3′‐anchor, such as (CA)8RG or (AGC)6TY. The resultant PCR reaction amplifies the sequence between two SSRs, yielding a multilocus marker system useful for fingerprinting, diversity analysis and genome mapping. PCR products are radiolabelled with32P or33Pviaend‐labelling or PCR incorporation, and separated on a polyacrylamide sequencing gel prior to autoradiographic visualisation. A typical reaction yields 20–100 bands per lane depending on the species and primer. We have used ISSR fingerprinting in a number of plant species, and report here some results on two important tropical species, sorghum and banana. Previous investigators have demonstrated that ISSR analysis usually detects a higher level of polymorphism than that detected with restriction fragment length polymorphism (RFLP) or random amplified polymorphic DNA (RAPD) analyses. Our data indicate that this is not a result of greater polymorphism genetically, but rather technical reasons related to the detection methodology used for

ISSN:0173-0835    

DOI:10.1002/elps.1150180906

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractMitochondrial DNA (mtDNA) is a valuable tool for the study of recent human evolution because it is easy to analyse, is inherited uniparentally and has a relatively rapid rate of evolution. mtDNA analysis has been used extensively for the elucidation of the pattern of migrations of human populations. Several studies have focused on the Pacific because Polynesia was settled by humans for the first time relatively recently and there is a wealth of archaeological and linguistic data to complement genetic data on the region. Results of mtDNA analyses on modern‐day Pacific populations indicate reduced genetic variability, and suggest that the Polynesians descend from people who migrated relatively recently from island Southeast Asia and that a population bottleneck occurred during the settlement of the central Pacific. Several informative polymorphisms have been identified in the hypervariable control region of mtDNA in modern‐day Pacific populations that are helpful in tracing the ancestral affinities of these people. Studies of these mtDNA polymorphisms in ancient bones of prehistoric Pacific islanders indicate that the proto‐Polynesian colonizers may have descended from the early settlers of island Melanesia. Although fraught with technical difficulties, studies of ancient DNA can provide valuable evidence on the genetic affinities of past pe

ISSN:0173-0835    

DOI:10.1002/elps.1150180907

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractThe human colonisation of Polynesia was a major event in world prehistory. It represents one of the last human population migrations, and one which required crossing major water barriers. Though the subject of Pacific population origins has been approached by scholars from numerous fields for nearly a century, recent years have seen the problem addressed by human geneticists [1–5]. Since the initial report describing the recovery of DNA from skeletal remains [6], ancient DNA studies have also focused on the Pacific region [7, 8]. In this paper we present the results of ancient DNA analyses ofRattus exulans, an animal that was transported by ancestral Polynesians through the Pacific to the far reaches of the Polynesian triangle. Analysis of DNA ofR. exulansskeletal remains has many advantages over studies of ancient human remains, yet the one drawback has been the recovery of ancient DNA from single bones of these very small rodents. We have successfully modified standard extraction protocols for ancient DNA [9] and have consistently extracted, amplified and sequenced mitochondrial DNA (mtDNA) from less than 0.1 g ofR. exulansbone and tooth samples recovered from archaeological sites throughout the Pacific, ranging from 400 to 2000 years ol

ISSN:0173-0835    

DOI:10.1002/elps.1150180908

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractPopulation structure has been revealed in mitochondrial D‐loop segment 1 (mt DLS1) sequences from Australian Aboriginal people in the Darling River region of NSW (Riverine) and from Yuendumu in central Australia (Desert). Comparison with five published global studies reveals that these Australians demonstrate greatest divergence from some Africans, least from Papua New Guinea (PNG) highlanders, and only slightly more divergence from some Pacific groups (Indonesian, Asian, Samoan, and coastal PNG). A median networks approach [1] demonstrates that several hypervariable nucleotide sites within the DLS1 are likely to have undergone mutation independently. A comprehensive evaluation of specific nucleotide variants with the large amount of global sequence data now available has been achieved in three stages of analysis: (i) identification of key nucleotide variants (from the Cambridge reference sequence [2]) in the Aboriginal Australian by pairwise comparison and construction of a ‘local’ median network, (ii) identification of key nucleotide variants in a selected global sample including Australian mtDLS1 types most different from each other, and (iii) calculation of the frequency with which these key nucleotide sites occur as variants in a greatly extended global sample. The third stage of the analysis revealed that nucleotides 16287 and 16356 are unique markers for representatives from the northern Riverine region. A ‘thymine’ at nucleotide 16223 is an informative signature of African and several identifiable non‐African DLS1 types, whereas the ‘cytosine’ form is a marker for European, Pacific, and some As

ISSN:0173-0835    

DOI:10.1002/elps.1150180909

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractPulsed field gel electrophoresis (PFGE), or electrophoretic karyotyping, separates chromosomal‐sized pieces of DNA in agarose gels where the orientation of the electric field is periodically altered. This technique has revealed that many fungi have a high degree of chromosomal length polymorphisms. Often the only isolates with identical karyotypes are derived from a single clone, thus PFGE provides a ‘genetic fingerprint’ for them. The size range and number of chromosomes within isolates of a particular species are usually constant, hence PFGE can distinguish between morphologically similar fungi. This technique can also be used to follow inheritance of chromosomal length polymorphisms and shows that in some fungi novel‐sized chromosomes are produced during meiosis. As well as resolving the nuclear (A‐type) chromosomes, it can also resolve dispensable (B‐type) chromosomes and cytoplasmic genomes including mitochondrial DNA and linear plasmids. The application of this technique to Australian isolates ofLeptosphaeria maculans, which causes blackleg disease of canola (Brassica napus), i

ISSN:0173-0835    

DOI:10.1002/elps.1150180910

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractWith the increase in the number of immunocompromised hosts, the number of fungal pathogens has increased markedly. Identification and classification, especially of yeast species and strains, is often difficult when based solely on phenotypic characteristics. Since it became clear that different fungal pathogens require specific treatment strategies, there is a need for simple, rapid and reliable methods to identify fungal isolates. Polymerase chain reaction (PCR) fingerprinting was successfully applied here to identify yeast isolates Microsatellite [(GTG)5; (GACA)4] and minisatellite [(5′GAGGGTGGCGGTTCT 3′), derived from the core‐sequence of the phage M13]specific primers were used as single primers in the PCR to amplify hypervariable interrepeat DNA sequences from over 200 European, American and Australian clinical isolates within the genusCandida.Each species, represented by its type strain, could be identified by a specific multilocus pattern, allowing for the assignment of all the isolates to the appropriate species. Intra‐species variation in the multilocus profiles was about 20% compared to inter‐species variation, which was up to 80%. Anamorph‐teleomorph pairs could be identified by highly homologous PCR fingerprint patterns. PCR fingerprinting was more discriminatory when compared with routinely used biochemical tests (Vitek YBC and API ID 32C). PCR fingerprinting has proven to be a powerful tool for the identification of medically important yeasts. It is rapid, sensitive, reliable, highly reproducible, stablein vitroandin vivo, and applicable to large‐scale experiments. Potential applications include: yeast taxonomy, epidemiology, environmental surveys, and improvement of the diagnosis of myc

ISSN:0173-0835    

DOI:10.1002/elps.1150180911

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY