Betül Kacar

From so simple a beginning endless forms most beautiful -- Charles Darwin

The modern synthesis of evolutionary theory and genetics has enabled us to recognize many underlying molecular mechanisms of organismal evolution. We know that in order to maximize an organism's fitness in a particular environment, individual interactions among the components of a system need to be optimized by natural selection as the organism responds to changes in the environment.

Despite the significant role of molecular interactions in determining an organism's adaptation to its environment, we still do not know how such inter and intra molecular interactions contribute to an organism's evolvability while maintaining the overall function. One way to address this challenge is to identify connections between molecular interactions (such as molecular networks) and their host organisms, and thus understand how such seemingly subtle interactions between intertwined molecules contribute to fitness.

I aim to make this connection experimentally, by integrating two disparate fields: ancestral sequence reconstruction and experimental evolution. Such a system allows me to rewind and replay the evolutionary history of ancient biomolecules in a modern context and understand the roles molecular tinkering plays in shaping evolutionary processes.

Here I briefly summarized my on-going projects. Please contact me for further information at betul AT gatech DOT edu.

EXPERIMENTAL EVOLUTION OF ANCIENT ELONGATION FACTOR PROTEINS

To assess the role of contingency in evolution, I insert previously resurrected Elongation Factor (EF-Tu) genes into modern bacterial genomes, then subject them to experimental evolution. To identify the changes in bacterial genotype throughout the evolutionary course, I then perform whole genome sequencing to initially identical evolved bacterial lineages. Observing the real-time evolution of ancient genes as they adapt to the conditions of modern bacteria allows me to analyze evolution in action.

UNDERSTANDING THE EVOLUTIONARY CONSTRAINTS ON THE EMERGENCE OF COMPLEX LIFE IN THE UNIVERSE

This study aims to identify planetary platforms likely to support Darwinian evolution and to predict the likelihood of life in the universe based on what is known of life (as we know it) here on Earth.

A REDUCTIONIST APPROACH TO UNDERSTAND PROTEIN EVOLUTION (case study:MAO)

Monoamine Oxidase (MAO) is the enzyme that degrades the primary amine neurotransmitters (i.e. dopamine, serotonin) in mammals. In other words, if the activity of MAO is inhibited, the amount of the respective neurotransmitters will sky-rocket.Mao-a and mao-b (monoamine oxidase) are the two of the genes that express MAO A and MAO B enzymes in mammals, respectively. Evolutionary studies show that mao-a and mao-b genes are formed by duplication of a single mao gene in the period of transition from aquatic to terrestrial environment. Phylogeny studies show that the closest ancestor of mammalian MAO is of teleost’s. Previously I developed an expression and purification system for zebrafish MAO and provided a detailed catalytic analysis. Currently, I am attempting to understand what kind of evolutionary events drove the duplication of these genes.