Dr. Vinod Kumar | Kumar Lab

Abstract:

Cycles in biological systems are all-pervasive in nature. Birds, like any other species, express daily rhythms in activity/rest, hormone secretion, and several other rhythmic characteristics. Most bird species also show long-term cycles in feeding behavior, body fattening (in migrants), reproduction, molt, or migration. Both daily and seasonal behaviors are under the strict control of the endogenous clock mechanisms, but the role of the environment remains critical for optimal performance and ultimately survival. Synchrony with the environment is achieved through the interaction of clock components with external cues (e.g. photoperiod), and internal coordination among different rhythmic physiological correlates is achieved through neural and endocrine signaling. Thus, we are interested to learn about how birds achieve precision in timing their daily and seasonal activities in sync with the periodic environment. Our research effort mainly centers around the “Avian Circadian and Seasonal Systems: Study from Behavior to Molecules”. The working hypothesis has been that specialized cells localized in different tissues express genes involved in the clock circuitry, and different cell populations control the food intake, body fattening, reproductive axis, molt, and migration, in a way that each event can be timed and spaced with each other to optimize an ecological adaptation. 

Click here for more information about Dr. Sarah Tishkoff.

Abstract:

Africa is thought to be the ancestral homeland of all modern human populations.  It is also a region of tremendous cultural, linguistic, climatic, and genetic diversity.   Despite the important role that African populations have played in human history, they remain one of the most underrepresented groups in human genomics studies. A comprehensive knowledge of patterns of variation in African genomes is critical for a deeper understanding of human genomic diversity, the identification of functionally important genetic variation, the genetic basis of adaptation to diverse environments and diets, and for reconstructing modern human origins. African populations practice diverse subsistence patterns (hunter-gatherers, pastoralists, agriculturalists, and agro-pastoralists) and live in diverse environments with differing pathogen exposure (tropical forest, savannah, coastal, desert, low altitude, and high altitude) and, therefore, are likely to have experienced local adaptation. In this talk I will discuss results of analyses of genome-scale genetic variation in geographically, linguistically, and ethnically diverse African populations in order to reconstruct human evolutionary history in Africa, African and African American ancestry, as well as the genetic basis of adaption to diverse environments.