Thursday, February 11th,

12:30pm

CGSB 8th floor seminar room

Andres Mansisidor, Hochwagen lab, NYU Biology

A position effect story: direct-repeat DNA recombines into

rDNA circles and super huge DNA arrays

In order to add mechanistic color to the “black box” that is repetitive DNA, our lab developed a novel approach for investigating the genetic activities of individual DNA repeats within the tandem repetitive ribosomal DNA array of Saccharomyces cerevisiae. Using this system, we have discovered that non-allelic homologous recombination, which is the major mechanism for maintaining the stability of this essential multi-copy locus, is subject to differential activity based on repeat position within the array. We have also found that proper chromosome condensation is critical for this positional bias, highlighting the importance of nuclear organization in the stabilization of repetitive DNA.

Dr. Antun Skanata, Kussell lab, NYU Biology Evolution of response networks in randomly fluctuating environments

Diverse biological processes, including viral epidemics, antibiotic resistance and cancer, occur under changing environmental conditions. Predicting reproductive growth of a population is the key to understanding how individuals have evolved their response to increase their chances of survival when their environments change. I develop evolutionary models to predict how bacteria use phenotypic memory to grow in fluctuating conditions. The model I will present exhibits a rich structure that points to the evolutionary pathways by which gene regulatory networks have optimized their response: either through an abrupt change in the structure of the regulatory network, or through continuously modifying the interactions between its components.

Pizza will be available free of charge.