GOTHENBURG, Sweden —Woody Allen might have coined it: the law of conservation of fragility. If part of a biological network gets stronger, some other part is bound to get weaker, new research shows. Its total fragility never gets better or worse, it just stays the same. Rather than being a statement of pessimism, this new law of conservation offers hope for finding better drug targets to treat diseases such as diabetes, heart disease and cancer, according to research presented by Hans V. Westerhoff, systems biologist at the Manchester Centre for Integrative Systems Biol...

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