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Trifolium species are native to the Mediterranean Basin where they are an important component of permanent pastures. A number of species have become naturalized in Australia and are agriculturally important in annual pastures. To understand the importance of genetic and ecotypic variation in the adaptation of Trifolium species to a new environment, seeds of three predominantly inbreeding and two predominantly outcrossing species of Trifolium were collected from 12 sites in Sardinia in 1998. Detailed ecogeographic information was collected at each site. The progeny were grown at the University of Western Australia Field Station at Shenton Park, Western Australia in 1999, and were scored for 10 morphological characters. Spatial analysis was applied to the data to improve the estimation of accession means, and to investigate the relationship with environmental variables that characterized the sites of collection. The spatially adjusted means were used as the basis for a principal components analysis. Ecogeographical factors at the sites of collection, particularly soil pH, are suggested to be more important than breeding system in determining the extent of genetic variation within the species. The species that showed the greatest genetic variation between accessions were the predominantly inbreeding species T. glomeratum and T. subterraneum, and the predominantly outcrossing species T. nigrescens. It is suggested that the wide genetic variation of these three species is largely due to their being in an ecogeographic environment close to their optimum, and to the possession of a mating system that is neither completely outcrossing nor completely self-fertilizing. The remaining two species, T. tomentosum and T. resupinatum, both occur more frequently on alkaline soils, and it is suggested that for the collected accessions of these two species the acid soils of Sardinia are a stressful environment that does not promote high levels of genetic variation. [ABSTRACT FROM PUBLISHER]

Heterogeneity is observed in the patterns of cognition in Alzheimer's disease (AD). Such heterogeneity might suggest the involvement of different etiological pathways or different host responses to pathology. A total of 627 subjects with mild/moderate AD underwent cognitive assessment with the Mini-Mental State Examination (MMSE) and the Dementia Rating Scale-2 (DRS-2). Latent class analysis (LCA) was performed on cognition subscale data to identify and characterize cognitive subgroups. Clinical, demographic, and genetic factors were explored for association with class membership. LCA suggested the existence of four subgroups; one group with mild and another with severe global impairment across the cognitive domains, one group with primary impairments in attention and construction, and another group with primary deficits in memory and orientation. Education, disease duration, age, Apolipoprotein E-epsilon4 (APOE epsilon4) status, gender, presence of grasp reflex, white matter changes, and early or prominent visuospatial impairment were all associated with class membership. Our results support the existence of heterogeneity in patterns of cognitive impairment in AD. Our observation of classes characterized by predominant deficits in attention/construction and memory respectively deserves further exploration as does the association between membership in the attention/construction class and APOE epsilon4 negative status.