Development of guidelines for family and non-professional helpers on assisting an older person who is developing cognitive impairment or has dementia: a Delphi expert consensus study.

BACKGROUND: Assisting a person with dementia can lead to significant carer burden and possible negative outcomes for the person. Using the Delphi method, this study developed expert consensus guidelines for how family and non-professional carers should assist a person who is developing cognitive impairment, or has dementia or delirium. METHODS: A systematic search of websites, books and journal articles was conducted to develop a questionnaire containing items about the knowledge, skills and actions needed for assisting a person who is developing cognitive impairment, or has dementia or delirium. These items were rated over three rounds by two international expert panels comprising professionals specialising in research or treatment of dementia, and dementia carer advocates. RESULTS: A total of 65 participants (43 in the professional panel and 22 in the carer advocate panel) completed all three survey rounds. Of the 656 survey items that were rated, a total of 389 items were endorsed by at least 80 % of each panel. The endorsed items formed the basis of a guidelines document that explains what family and non-professional carers need to know and do when assisting a person who is developing cognitive impairment, or has dementia or delirium. CONCLUSIONS: The two groups of experts were able to reach substantial consensus on how to assist a person who is developing cognitive impairment, or has dementia or delirium.

The genetic diversity of UK, US and Australian cultivars of Triticum aestivum measured by DArT markers and considered by genome.

The genetic diversity of UK, US and Australian wheat varieties over the period of modern plant breeding is estimated using diversity array technology markers. Diversity is assessed by both genetic distance between varieties, by AMOVA and as the volumes of multi-dimensional convex hulls estimated from principal co-ordinate analysis. At the whole genome level the three populations are genetically distinct; this is also true of the B genome. However, the US and Australian D genomes are found to occupy the same region of diversity space and the A genomes for these countries are partially overlapping. The use of high-density genotyping with a common marker set allows an unprecedented direct comparison between the diversities of the national populations, between individual genomes and the fluctuation of diversity over time. The highest genetic diversity amongst varieties is reported in the Australian population followed by the US, which in turn is more diverse than the UK. However the average diversity of loci is higher in the US set than in the Australian. Non-random fluctuations in genetic diversity over time are observed.

A genetic map of 1,000 SSR and DArT markers in a wide barley cross.

A high-density genetic map was developed from an F1-derived doubled haploid population generated from a cross between cultivated barley (Hordeum vulgare) and the subspecies H. vulgare ssp. spontaneum. The map comprises 1,000 loci, amplified using 536 SSR (558 loci) and 442 DArT markers. Of the SSRs, 149 markers (153 loci) were derived from barley ESTs, and 7 from wheat ESTs. A high level of polymorphism ( approximately 70%) was observed, which facilitated the mapping of 197 SSRs for which genetic assignments had not been previously reported. Comparison with a published composite map showed a high level of co-linearity and telomeric coverage on all seven chromosomes. This map provides access to previously unmapped SSRs, improved genome coverage due to the integration of DArT and EST-SSRs and overcomes locus order issues of composite maps constructed from the alignment of several genetic maps.

Sequence tagged microsatellites for the Xgwm533 locus provide new diagnostic markers to select for the presence of stem rust resistance gene Sr2 in bread wheat ( Triticum aestivum L.).

The stem rust resistance gene Sr2 has provided durable broad-spectrum, adult-plant resistance to the fungal pathogen Puccinia graminis Pers. f. sp. tritici throughout wheat-growing regions of the world for more than 50 years. The ability to select for Sr2 in wheat breeding programs was recently improved by the identification of a tightly linked microsatellite marker gwm533. This marker typically amplifies a 120-bp polymerase chain reaction fragment from wheat lines carrying Sr2. In instances where the 120-bp fragment is not associated with the presence of Sr2, DNA sequence analysis has shown that a second allele was amplified, differing in the structure of the microsatellite repeat. To discriminate this allelic homoplasy (alleles identical in size, but not identical by descent), sequence-tagged microsatellites (STM) markers were developed for the Xgwm533 locus. These markers were shown to be diagnostic for the presence of Sr2 in a wide range of germplasm, representative of all major wheat varieties historically grown in Australia. The STMs will be particularly useful for marker-assisted selection in Southern Australian breeding programs, where the use of the marker gwm533 is often precluded by the presence of the non- Sr2-associated 120-bp allele in the pedigree of current breeding germplasm. The STMs also revealed a high incidence of previously undetected allelic homoplasy at the Xgwm533 locus and may have broader utility in genetic research and breeding, as this locus is also reported to be strongly associated with a major gene conferring resistance to Fusarium head blight.

Genetic diversity in Australian wheat varieties and breeding material based on RFLP data.

Restriction fragment length polymorphisms (RFLPs) have been used to characterise the genetic diversity of wheat (Triticum aestivum) germplasm. One hundred and twenty-four accessions comprising all major Australian wheat varieties and lines important for breeding purposes were assayed for RFLPs with clones of known genetic location and selected to give uniform genome coverage. The objectives of this study were to determine RFLP-based genetic similarity between accessions and to derive associations between agronomically significant traits and RFLP phenotypes. Ninety-eight probes screened against genomic DNA digested with five restriction endonucleases detected a total of 1968 polymorphic fragments. Genetic similarity (GS) calculated from the RFLP data ranged from 0.004 to 0.409 between accessions, with a mean of 0.18. Cluster analysis based on GS estimates produced four groupings that were generally consistent with available pedigree information. Comparisons of the RFLP phenotypes of accessions containing disease resistance genes present on introgressed alien segments enabled the identification of specific alleles characteristic of these regions. Associations were derived for a range of stem-rust, leaf-rust and yellow-rust resistance genes. These results suggest that RFLP analysis can be used for the characterisation and grouping of elite breeding material of wheat and RFLP profiling can identify chromosome segments associated with agronomic traits.

RAPD and organelle specific PCR re-affirms taxonomic relationships within the genus Coffea.

The phenetic relationships between 18 Coffea accessions representing 11 of the most important Coffea species employed in current breeding programmes were examined using RAPD markers and chloroplast and mitochondrial genome specific sequence tagged sites (STS). Estimates of variability based on the number of shared RAPD amplification products placed the species into three distinct groups which were consistent with derived chloroplast DNA phenotypes, the geographical origins of the species and previous studies based on morphological characteristics and RFLPs. C. eugenioides (2n = 2x = 22) exhibited the greatest similarity to the cultivated C. arabica (2n = 4x = 44) and may represent its maternal progenitor. The results are discussed in the context of strategies for Coffea improvement.

Polymerase chain reaction-based assays for the characterisation of plant genetic resources.

Plant genetic resources are an important component of biodiversity and provide the basic genetic variability that allow new and improved cultivars to be developed. Numerous germplasm collections have been established and it is important to established that such collections are representative and accessible to breeders and biotechnologists. Molecular markers provide the best estimate of genetic diversity since they are independent of the confounding effects of environmental factors. Assays based on the polymerase chain reaction (PCR) are considered to meet both the technical and genetical requirements for the characterisation of plant and animal genetic resources. Two main approaches are described, based on anonymous and defined primers. The use of both randomly amplified polymorphic DNA (RAPD) and microsatellites or simple sequence repeats (SSR) for the characterisation of perennial tree species, and distribution of variability within gene pools is reported. The detection of interspecific gene introgression between coffee species with RAPD markers is described together with the use of microsatellites to genotype potato. The use of PCR-based assays will facilitate the evaluation and utilisation of plant genetic resources.

Detection of quantitative trait loci for agronomic, yield, grain and disease characters in spring barley (Hordeum vulgare L.).

Quantitative trait loci (QTLs) have been revealed for characters in a segregating population from a spring barley cross between genotypes adapted to North-West Europe. Transgressive segregation was found for all the characters, which was confirmed by the regular detection of positive and negative QTLs from both parents. A QTL for all the agronomic, yield and grain characters measured except thousand grain weight was found in the region of the denso dwarfing gene locus. There were considerable differences between the location of QTLs found in the present study and those found in previous studies of North American germ plasm, revealing the diversity between the two gene pools. Thirty-one QTLs were detected in more than one environment for the 13 characters studied, although many more were detected in just one environment. Whilst biometrical analyses suggested the presence of epistasis in the genetic control of some characters, there was little evidence of interactions between the QTLs apart from those associated with yield. QTLs of large effect sometimes masked the presence of QTLs of smaller effect.

Evaluation of the extent of genetic variation in mahoganies (Meliaceae) using RAPD markers.

Despite the economic importance of mahoganies (Meliaceae) little is known of the pattern of genetic variation within this family of tropical trees. We describe the application of a polymerase chain reaction (PCR)-based polymorphic DNA assay procedure random amplified polymorphic DNAs (RAPDs) to assess the extent of genetic variation between eight mahogany species from four genera. Pronounced genetic differentiation was found between the species and genera. There was a clear separation of Cedrela odorata from the other species, with 95% of the variable amplification products differing, whereas Lovoa trichilioides, Khaya spp. and Swietenia spp. were more closely grouped. These results are consistent with the current taxonomic viewpoint. A number of markers were found to be diagnostic for particular species, which could be of value in determining the status of putative hybrids. The application of RAPDs to the study of genetic variation in mahoganies is discussed in the context of developing genetic conservation and improvement strategies for these species.

Detection of genetic diversity and selective gene introgression in coffee using RAPD markers.

RAPD (randomly amplified polymorphic DNA) markers generated by arbitary decamers have been successfully employed to detect genetic polymorphisms between coffee species and between Coffea arabica genotypes. The RAPD profiles were used to construct dendrograms and these were consistent with the known history and evolution of Coffea arabica. Material originating from Ethiopia and the arabica sub-groups - C. arabica var. typica and C. arabica var. bourbon - were clearly distinguished. RAPD analysis therefore reflects morphological differences between the sub-groups and the geographical origin of the coffee material. Species-specific amplification products were also identified, but, more importantly, amplification products specific to C. canephora were identified in two C. arabica genotypes, Rume Sudan and Catimor 5175. This diagnostic product is therefore indicative of interspecific gene flow in coffee and has biological implications for selective introgressive hybridisation in coffee. Our study demonstrates the power of the polymerase chain reaction technology for the generation of genetic markers for long-lived perennial tree and bush crops.

Molecular mapping of genes determining height, time to heading, and growth habit in barley (Hordeum vulgare).

A combination of random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers has been used to locate genes controlling important developmental characters in barley. The denso dwarfing gene has been mapped to the long arm of chromosome 3H. Stepwise multiple regression was also used to identify another region of the barley genome (on chromosome 7H), which contributed to variation in height. The denso locus was shown to be associated with delaying time to heading. A protein (WSP2) and an RAPD marker on barley chromosomes 5H and 6H, respectively, were also associated with time to heading. These results are discussed in relation to the genetic analysis of developmentally important traits and the development of dwarfing genes in barley breeding programs.

Identification of RAPD markers linked to a Rhynchosporium secalis resistance locus in barley using near-isogenic lines and bulked segregant analysis.

Three hundred random sequence 10-mer primers were used to screen a pair of near-isogenic lines of barley and their donor parent for markers linked to genes conferring resistance to Rhynchosporium secalis. One primer was identified which reproducibly generated a product, SC10-65-H400, from the donor parent and the Rhynchosporium-resistant near-isogenic line but not from the recurrent parent. Segregation analysis on a barley doubled haploid population and examination of a further three near-isogenic lines, their donor and recurrent parents confirmed that this marker was linked to the Rhynchosporium resistance locus (Rh) on chromosome 3L. The presence or absence of SC10-65-H400 was subsequently used along with the resistance phenotype to identify two groups of individuals in the doubled haploid population which possessed alternative alleles at both loci and defined a genetic interval between these two markers. Based on that information two bulked DNA samples were constructed by combining equal amounts of DNA from five individuals from each group. The two bulks and doubled haploid parental lines were screened with 700 10-mer primers. Seven products were identified which were present in the 'resistant' bulk and parent and were absent in the susceptible samples. Segregation analysis established their association with Rh. In addition co-segregation of the linked markers with a set of chromosome arm specific RFLPs confirmed the location of the Rh locus on the long arm of barley chromosome 3.

Detection and analysis of genetic variation in Hordeum spontaneum populations from Israel using RAPD markers.

Randomly amplified polymorphic DNA (RAPD) markers were used to analyse genetic diversity within and between Hordeum spontaneum populations sampled from Israel. Nei's index of genetic differentiation was used to partition diversity into within and between population components. Fifty-seven per cent of the variation detected was partitioned within 10 H. spontaneum populations. Using principal component and multiple regression analysis, part of the variation detected between populations was seen to be associated with certain ecogeographical factors. Fifty-eight per cent of the distribution of the phenotypic frequencies of three RAPD phenotypes detected using a single primer in 20 H. spontaneum populations could be accounted for by four ecogeographical variables, suggesting adaptive variation at certain RAPD loci.

Identification of RAPD markers linked to genetic factors controlling the milling energy requirement of barley.

Doubled haploid (DH) populations of barley have been used in combination with PCR-based polymorphic-assay procedures to identify molecular markers linked to genes controlling the milling energy requirement of the grain. Milling energy (ME) is a quantitative trait and locating individual quantitative trait loci (QTLs) involved the construction of bulks by combining DNA from DH families representing the extreme members of the distribution for ME. In addition, the individuals had alternative alleles at theRrn2 locus that has previously been shown to be linked to an ME QTL. The DNA bulks were screened with Randomly Amplified Polymorphic DNA (RAPD) markers and polymorphic amplification products tested for linkage to genes influencing the expression of ME in a DH population. Several markers were identified which are linked to a QTL controlling ME and the recombination fraction determined by maximum likelihood procedures. The results indicate that DHs in combination with RAPDs and bulked segregant analysis provide an efficient method for locating QTLs in barely. Furthermore, this approach is applicable to mapping other QTLs in a range of organisms from which DH or recombinant inbred lines can be extracted.

Detection of genetic variation between and within populations of Gliricidia sepium and G. maculata using RAPD markers.

Gliricidia sepium and G. maculata are multi-purpose leguminous trees native to Central America and Mexico. Research programmes have been initiated to define the native distribution of Gliricidia and sample the spectrum of genetic variation. To date, there has been little systematic assessment of genetic variability in multi-purpose tree species. Accurate estimates of diversity between- and within-populations are considered a prerequisite for the optimization of sampling and breeding strategies. We have used a PCR-based polymorphic assay procedure (RAPDs) to monitor genetic variability in Gliricidia. Extensive genetic variability was detected between species and the variability was partitioned into between- and within-population components. On average, most (60 per cent) of the variation occurs between G. sepium populations but oligonucleotide primers differed in their capacity to detect variability between and within populations. Population-specific genetic markers were identified. RAPDs provide a cost-effective method for the precise and routine evaluation of variability and may be used to identify areas of maximum diversity. The approaches outlined have general applicability to a range of organisms and are discussed in relation to the exploitation of multi-purpose tree species of the tropics.

Grain isozyme and ribosomal DNA variability in Hordeum spontaneum populations from Israel.

Grain isozyme and ribosomal DNA (rDNA) variability was examined in Hordeum spontaneum populations sampled from 27 geographical sites in Israel. Considerable phenotypic variability was observed with variants of ADH1, EST3, EST10, BMY1 and WSP detected, which are not available in the H. vulgare gene pool. Seven new rDNA phenotypes were detected in the H. spontaneum populations. Shannon's index of diversity was used to partition the total phenotypic variation into between and within population components. Most of the variation occurred between H. spontaneum populations. The distribution of both grain isozyme and rDNA phenotypes was non-random and correlated with a range of ecogeographical factors. In particular, the G phenotype of BMY1 was restricted to the Negev Desert and Dead Sea regions of Israel. Over 78% of the variation in the frequency of this particular phenotype could be explained by the number of rainy days per year and mean temperature in January. This suggests that variation at this locus or at loci linked to it may be of adaptive significance and of value in the introgression of genes controlling abiotic stress tolerance from H. spontaneum into the H. vulgare gene pool.