New horizons in frailty: the contingent, the existential and the clinical

In the past decade, frailty research has focused on refinement of biomedical tools and operationalisations, potentially introducing a reductionist approach. This article suggests that a new horizon in frailty lies in a more holistic approach to health and illness in old age. This would build on approaches that view healthy ageing in terms of functionality, in the sense of intrinsic capacity in interplay with social environment, whilst also emphasising positive attributes. Within this framework, frailty is conceptualised as originating as much in the social as in the biological domain; as co-existing with positive attributes and resilience, and as situated on a continuum with health and illness. Relatedly, social science-based studies involving interviews with, and observations of, frail, older people indicate that the social and biographical context in which frailty arises might be more impactful on the subsequent frailty trajectory than the health crisis which precipitates it. For these reasons, the article suggests that interpretive methodologies, derived from the social sciences and humanities, will be of particular use to the geriatrician in understanding health, illness and frailty from the perspective of the older person. These may be included in a toolkit with the purpose of identifying how biological and social factors jointly underpin the fluctuations of frailty and in designing interventions accordingly. Such an approach will bring clinical approaches closer to the views and experiences of older people who live with frailty, as well as to the holistic traditions of geriatric medicine itself

Phylogeny of a rapidly evolving clade: The cichlid fishes of Lake Malawi, East Africa

Lake Malawi contains a flock of \u3e500 species of cichlid fish that have evolved from a common ancestor within the last million years. The rapid diversification of this group has been attributed to morphological adaptation and to sexual selection, but the relative timing and importance of these mechanisms is not known. A phylogeny of the group would help identify the role each mechanism has played in the evolution of the flock. Previous attempts to reconstruct the relationships among these taxa using molecular methods have been frustrated by the persistence of ancestral polymorphisms within species. Here we describe results from a DNA fingerprinting technique that overcomes this problem by examining thousands of polymorphisms distributed across the genome. The resulting dendrogram averages the evolutionary history of thousands of genes and should accurately reflect the evolutionary history of these species. Our tree resolves relationships among closely related Lake Malawi cichlids and provides insights into the pattern of speciation in this group. We demonstrate that adaptive divergence in trophic morphology played an important role during the early history of the lake. Subsequent species diversity has arisen with little change in trophic morphology, which suggests that other forces are responsible for the continued speciation of these fishes