Diversity of lactase persistence in African milk drinkers

The genetic trait of lactase persistence is attributable to allelic variants in an enhancer region upstream of the lactase gene, LCT. To date, five different functional alleles, -13910*T, -13907*G, -13915*G, -14009*G and -14010*C, have been identified. The co-occurrence of several of these alleles in Ethiopian lactose digesters leads to a pattern of sequence diversity characteristic of a 'soft selective sweep'. Here we hypothesise that throughout Africa, where multiple functional alleles co-exist, the enhancer diversity will be greater in groups who are traditional milk drinkers than in non-milk drinkers, as the result of this sort of parallel selection. Samples from 23 distinct groups from 10 different countries were examined. Each group was classified 'Yes 'or 'No' for milk-drinking, and ethnicity, language spoken and geographic location were recorded. Predicted lactase persistence frequency and enhancer diversity were, as hypothesised, higher in the milk drinkers than the non-milk-drinkers, but this was almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a north-east to south-west decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection, the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition

Rhetoric vs. realities—An assessment of rainwater management planning and implementation modalities in Oromia and Amhara regions, Ethiopia

This paper is the first in a series of three interrelated papers and focuses on planning and implementation modalities of Rainwater Management (RWM) Strategies. It is part of the NBDC project ‘On integrated RWM strategies—technologies, institutions and policies’. The project is underpinned by the recognition that integrated RWM needs to combine technologies, policies and institutions and be developed through multi-stakeholder engagement to foster innovation. Three woredas were selected for the research—Jeldu and Diga in Oromia Region and Fogera in Amhara Region. The research on planning and implementation of RWS is guided by the hypothesis that there is a gap between available policy and guidelines and specific planning and implementation procedures. Research findings conclude that RWM planning and implementation is still rather top–down and technology-oriented instead of people-centred. Local processes are not in place to take account of different livelihood strategies and constraints, cultural, social or institutional dynamics as well as power relations and gender issues. The research concludes with six recommendations, largely aimed at Ethiopian policymakers and implementing agencies, suggesting an alternative approach to RWM planning and implementation processes which would help improve the impact, sustainability and local ownership of interventions. The paper outlines RWM strategies which are developed with true participation of farmers and other stakeholders; are based on evidence of what works and why; take into account specific socioeconomic and ecological niches; work across relevant sectors; and support local opportunities for innovation