Tatar Research Lab

Molecular genetic approach

With Drosophila melanogaster we investigate mutations that affect rates of aging. Mutants of the insulin-like receptor (InR) increase life span by 50-85%. InR is a homolog of C. elegans daf-2, which was among the first genes recognized to modulate aging. Mutants of InR possess many phenotypes that could extend life: high fat content, small body size and reduced fecundity. We found that reduce fecundity results from deficiency of the endocrine juvenile hormone, and that this hormonal itself is sufficient to modulate adult aging in the fly.
Our current aim is to understand how insulin and the insulin-like receptor modulate neuroendocrine synthesis of juvenile hormone, and in turn how this hormone affects somatic traits with respect to aging. Our strategy is to integrate genetic, molecular and physiological techniques to develop a comprehensive model for the regulation and cause of Drosophila aging.

Biology of aging in natural populations

Melanoplus grasshoppers of the Sierra Nevada occur along an elevational gradient. Populations are genetically differentiated in a number of life history traits; senescence is fastest in adults from high elevations. In the laboratory, we use stocks derived from field populations to explore the genetic and demographic basis of aging. Our current aim is to distinguish the relative importance of pleiotropy versus mutation and drift as the genetic basis of senescence evolution. One future goal is to return to the field and establish whether the age-specific patterns of natural selection are sufficient to predict the evolved patterns of aging revealed by detailed laboratory demographics.

Drosophila also provide opportunities to assess the ecological context of senescence evolution. Endemic Drsophila of Japan and of Finland overwinter as adults in a state of photoperiod induced reproductive diapause. We find that this diapause is associated with negligible rates of aging. With these endemic species we are beginning to explore the physiological basis of senescence plasticity. We hope to extend this work into the realm of comparative genomics through the cross-hybridization of with D. melanogaster spotted arrays.

Somatic and reproductive aging in primates

Baboons are perhaps the best primate model to study the genetics and demography of aging. Wild populations in East Africa reveal robust patterns of demographic senescence that are mirrored by a captive population at the Southwest Regional Primate Center. In collaboration with field, clinical and laboratory scientists I am developing an initiate to characterize the aging phenotypes of baboon and to genetically map loci that lead to differences in senescence and female perimenopause.

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