975 resultados para POLYMORPHIC CHARACTERS
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Mode of access: Internet.
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Vol. III contains a complete monograph ofthe Menispermaceæ.
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Kennedy's disease (spinobulbar muscular atrophy) is an X-linked form of motor neuron disease affecting adult males carrying a CAG trinucleotide repeat expansion within the androgen receptor gene. While expression of Kennedy's disease is thought to be confined to males carrying the causative mutation, subclinical manifestations have been reported in a few female carriers of the disease. The reasons that females are protected from the disease are not clear, especially given that all other diseases caused by CAG expansions display dominant expression. In the current study, we report the identification of a heterozygote female carrying the Kennedy's disease mutation who was clinically diagnosed with motor neuron disease. We describe analysis of CAG repeat number in this individual as well as 33 relatives within the pedigree, including two male carriers of the Kennedy's mutation. The female heterozygote carried one expanded allele of the androgen receptor gene with CAG repeats numbering in the Kennedy's disease range (44 CAGs), with the normal allele numbering in the upper-normal range (28 CAGs). The subject has two sons, one of whom carries the mutant allele of the gene and has been clinically diagnosed with Kennedy's disease, whilst the other son carries the second allele of the gene with CAGs numbering in the upper normal range and displays a normal phenotype. This coexistence of motor neuron disease and the presence of one expanded allele and one allele at the upper limit of the normal range may be a coincidence. However, we hypothesize that the expression of the Kennedy's disease mutation combined with a second allele with a large but normal CAG repeat sequence may have contributed to the motor neuron degeneration displayed in the heterozygote female and discuss the possible reasons for phenotypic expression in particular individuals.
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Environmentally-related wear conditions and pathologies affecting the dentition of fossil lungfish from freshwater deposits in Australia have been analysed and compared with similar changes in the dentition of the living Australian lungfish, Neoceratodus forsteri. Fossil populations from the Namba, Etadunna, Wipajiri and Katipiri formations in central Australia, and the Carl Creek Limestone and the Camfield beds in northern Australia were assessed. Tooth plates from populations of living lungfish from the Brisbane River and Enoggera Reservoir in southeast Queensland were analysed for comparison. Tooth plates were measured to determine the numbers of different age groups in each population. They were assessed for abrasion, attrition, spur and step wear, erosion and caries, and for trauma and pathological conditions such as malocclusion, hyperplasia, abscesses, osteopenia and parasitic damage. All of these conditions are related to the environment where the fish lived, are found in living members of the group, and can be compared directly with those of fossil relatives. The results suggest that some of the fossil populations were at risk before climatic changes late in the Cainozoic destroyed their habitats. Some fossil lungfish populations, such as those of the Wipajiri Formation, exhibit active spawning and recruitment, good growth rates and a low incidence of disease and environmentally related damage to the tooth plates. Others, like those of the Katipiri and Namba Formations, include no young, and the adult fish were ageing and show environmentally-related damage to the dentition. Etadunna lungfish had active recruitment, but the tooth plates show a high incidence of attrition and caries. Riversleigh lungfish were actively spawning but did not grow large. Tooth plates from this latter deposit have a high incidence of pathological conditions. Fish from the Camfield Beds, where food was severely limiting, had little serious pathology but high levels of caries. Pathologies among living lungfish are common, but fossil fish were comparatively healthy, with few serious dental problems. Information from studies of fossil lungfish confirms that conservation of the few living species of lungfish depends on the maintenance of clean environments that provide adequate supplies of food and suitable sites for spawning and for the growth of young fish.
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The use of morphological data obtained from field (plot test) and glasshouse trials to identify and discriminate among four Iranian and two New Zealand lucerne (Medicago sativa L.) cultivars was investigated, following guidelines established by the International Union for the Protection of New Varieties of Plants (UPOV) for cultivar registration and the Organisation for Economic Co-operation and Development (OECD) for seed certification. Data were collected for terminal leaflet length, width and ratio, angle of stem growth, date of first flowering, stem height at first flowering, flower colour, cutting recovery height, and disease scores. None of these characters were sufficient to identify or discriminate among the six cultivars. The results indicate a need to find cost-effective and efficient laboratory techniques to enhance the assessment of distinctness of lucerne cultivars (UPOV) and for determining cultivar purity for lucerne seed certification (OECD).
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We isolated 13 polymorphic microsatellite markers from the satin bowerbird, Ptilonorhynchus violaceus from a genomic library enriched in (AAGG)(n) repetitive elements and characterized them in 20 individuals. The number of alleles ranged from two to 18 per locus with the observed heterozygosity ranging from 0.15 to 1.00. These markers will be useful for analysing questions concerning parentage, population genetic structure and models of speciation.
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We isolated 12 polymorphic microsatellite markers for the large-billed scrubwren Sericornis magnirostris from genomic libraries enriched for (AAGG)(n) and (AACC)(n) repetitive elements and characterized them in 11 individuals. The number of alleles ranged from four to 15 per locus with the observed heterozygosity ranging from 0.14 to 0.91. These markers will be useful to address questions concerning population genetic structure and models of speciation.
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We isolated 12 polymorphic microsatellite markers for the grey-headed robin Poecilodryas albispecularis from genomic libraries enriched for (AAGG)n and (AACC)n repetitive elements and characterized them in 12 individuals. The number of alleles ranges from three to nine per locus with the observed heterozygosity ranging from 0.33 to 0.90. These markers will be useful for analysis of questions concerning population genetic structure and testing models of speciation.
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Based on morphological features alone, there is considerable difficulty in identifying the 5 most economically damaging weed species of Sporobolus [ viz. S. pyramidalis P. Beauv., S. natalensis ( Steud.) Dur and Schinz, S. fertilis ( Steud.) Clayton, S. africanus (Poir.) Robyns and Tourney, and S. jacquemontii Kunth.] found in Australia. A polymerase chain reaction (PCR)-based random amplified polymorphic DNA ( RAPD) technique was used to create a series of genetic markers that could positively identify the 5 major weeds from the other less damaging weedy and native Sporobolus species. In the initial RAPD pro. ling experiment, using arbitrarily selected primers and involving 12 species of Sporobolus, 12 genetic markers were found that, when used in combination, could consistently identify the 5 weedy species from all others. Of these 12 markers, the most diagnostic were UBC51(490) for S. pyramidalis and S. natalensis; UBC43(310,2000,2100) for S. fertilis and S. africanus; and OPA20(850) and UBC43(470) for S. jacquemontii. Species-specific markers could be found only for S. jacquemontii. In an effort to understand why there was difficulty in obtaining species-specific markers for some of the weedy species, a RAPD data matrix was created using 40 RAPD products. These 40 products amplified by 6 random primers from 45 individuals belonging to 12 species, were then subjected to numerical taxonomy and multivariate system (NTSYS pc version 1.70) analysis. The RAPD similarity matrix generated from the analysis indicated that S. pyramidalis was genetically more similar to S. natalensis than to other species of the 'S. indicus complex'. Similarly, S. jacquemontii was more similar to S. pyramidalis, and S. fertilis was more similar to S. africanus than to other species of the complex. Sporobolus pyramidalis, S. jacquemontii, S. africanus, and S. creber exhibited a low within-species genetic diversity, whereas high genetic diversity was observed within S. natalensis, S. fertilis, S. sessilis, S. elongates, and S. laxus. Cluster analysis placed all of the introduced species ( major and minor weedy species) into one major cluster, with S. pyramidalis and S. natalensis in one distinct subcluster and S. fertilis and S. africanus in another. The native species formed separate clusters in the phenograms. The close genetic similarity of S. pyramidalis to S. natalensis, and S. fertilis to S. africanus may explain the difficulty in obtaining RAPD species-specific markers. The importance of these results will be within the Australian dairy and beef industries and will aid in the development of integrated management strategy for these weeds.
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We have isolated 16 polymorphic microsatellite markers for the green-eyed tree frog, Litoria genimaculata, from genomic libraries enriched for (AAGG)(n) and (AAAG)(n) repetitive elements. The number of alleles ranges from four to 14 per locus with the observed heterozygosity ranging from 0.36 to 1.00. These markers will be useful for analysis of questions concerning population genetic structure and speciation.
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We have isolated 18 polymorphic microsatellite loci for Cophixalus ornatus from genomic libraries enriched for (AAAG)(n), (AACC)(n) and (AAGG)(n) repetitive elements. The number of alleles ranges from five to 22 per locus with the observed heterozygosity ranging from 0.10 to 0.92. These markers will be useful for the analysis of population structure in C. ornatus and testing alternative models of speciation.
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We report on the development and characterization of 14 polymorphic microsatellite loci in the zebra shark (Stegostoma fasciatum). Five tetranucleotide and nine dinucleotide loci were polymorphic with heterozygosities ranging from 0.400 to 0.967 and from three to 22 alleles per locus. Cross-species amplification of these zebra shark primers on four other species of orectolobid sharks was not successful.