09/14 Symposium: World Leaders

Symposium: World Leaders in Evolutionary Medicine

Friday Sept 14 Special Symposium 8:30 AM-12:30 PM in M1020 SPH II (Large Auditorium)

No fee, all welcome.   Advance registration not required

8:30  Coffee, tea and conversation

9:00 Randolph Nesse, Psychiatry, Psychology, ISR, and the Evolution and Human Adaptation Program University of Michigan

        Evolutionary Medicine Comes of Age

9:15 Stephen Stearns, Evolutionary Biology, Yale University

        Evolutionary medicine: Recent progress and current questions that urgently need answers

I will first survey the range of topics covered in evolutionary medicine, highlighting the particular interest of several of them.  I will then focus in the middle of the talk on one subject where recent success has been surprising: worm therapy for autoimmune disease.  In the last third of the talk I will discuss twelve questions raised by recent research where getting answers is particularly pressing because each of them points to potential solutions to serious problems. 

10:15 Break

10:30 Cynthia Beall, Anthropology, Case Western Reserve

         Evolution and human genetic adaptation to high altitude

Populations native to the Tibetan and Andean Plateaus are descended from colonizers who arrived perhaps 25,000 and 11,000 years ago, respectively. Both have been exposed to the opportunity for natural selection for traits that offset the unavoidable environmental stress of severe lifelong high-altitude hypoxia. This paper presents evidence that Tibetan and Andean high-altitude natives have adapted differently, as indicated by large quantitative differences in numerous physiological traits comprising the oxygen delivery process. These findings suggest the hypothesis that evolutionary processes have tinkered differently on the two founding populations and their descendents, with the result that the two followed different routes to the same functional outcome of successful oxygen delivery, long-term persistence and high function. Assessed on the basis of basal and maximal oxygen consumption, both populations avail themselves of essentially the full range of oxygen-using metabolism as populations at sea level, in contrast with the curtailed range available to visitors at high altitudes. Efforts to identify the genetic bases of these traits have included quantitative genetics, genetic admixture, and candidate gene approaches. These reveal generally more genetic variance in the Tibetan population and more potential for natural selection. There is evidence that natural selection is ongoing in the Tibetan population, where women estimated to have genotypes for high oxygen saturation of hemoglobin (and less physiological stress) have higher offspring survival. Identifying the genetic bases of these traits is crucial to discovering the steps along the Tibetan and Andean routes to functional adaptation.

11:30 Sir Peter Gluckman FRS, University Distinguished Professor, Centre for Human Evolution, Adaptation and Disease, Liggins Institute, University of Auckland

         Evolution and epigenetics; mismatched living in a mismatched world

The genotype alone does not determine phenotype - rather the process of developmental plasticity,mediated by epigenetic mechanisms mould early development in response to the perceived or predicted environment. Such conserved mechanisms allow organisms to survive transient changes in environmental states that may persist for a few generations but a rapid change in the environment may leave the organism mismatched to the world they are living in. There is mounting evidence for trans-generationally and developmentally induced effects on the individual vulnerability to disease and compelling evidence that the conditions of embryonic and fetal life influence the risk of developing in later life obesity, cardiovascular disease, type two diabetes mellitus and osteoporosis. Importantly these effects are not restricted to the extremes of the developmental environment – rather they occur across the normative range of fetal states suggesting an adaptive origin. Experimental studies supported by clinical observations demonstrate that these maternal effects are mediated through epigenetic changes in specific generally non–imprinted genes. Such outcomes can be understood as a result of both evolutionary and developmental mismatch. We have developed an adaptive model supported by empirical evidence to explain the circumstances under which maladaptive consequences can arise from the normative processes of adaptive plasticity. The environments we now live in can be considered as evolutionarily novel in that we experience more extreme nutritional loads than we evolved to cope with but is is the nature of developmental mismatch, that is between the early life environment experienced in utero and that experienced in later life, that creates individual variation in their sensitivity to an obesogenic world.Recent changes in the epidemiology of non-communicable disease can be understood in the light of these effects The same model can be applied to other domains including the behavioral domain. The range of trans-generational mechanisms that can operate allow environmental knowledge from one generation to pass to the next. While not Lamarckian, broader concepts of inheritance are needed than simply fixed genetic variation.

12:30  Lunch and discussion for  participants who register by Monday Sept 10