IMEG

Institute of Molecular
Evolutionary Genetics

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

IMEG SEMINARS
SPRING 2014

 

Previous IMEG Seminars and Abstracts:

Spring 2014

Fall 2013

Spring 2013

Fall 2012

 

Spring 2012

Fall 2011

Fall 2010

 

Spring 2010
Fall 2009

Spring 2009

Fall 2008

Spring 2008

Fall 2007
Spring 2007
Fall 2006

Spring 2006
Fall 2005
Spring 2005

Fall 2004

Spring 2004

Fall 2003

Spring 2003
Fall 2002

Date

Speaker

01/23/14

(Thurs)

11:00 AM

W203 MSC

HUCK INSTITUTE LECTURE - Infectious Disease Dynamics

 

Speaker: Dr. Frank Jiggins – University of Cambridge – Dept. of Genetics

 

Title: Evolution and Genetics of Susceptibility to Infection: Insights from Drosophila and Mosquitoes

 

Abstract:

01/27/14

(Mon)

12:10 PM

108 Wartik

HUCK INSTITUTE LECTURE - Plant Biology

 

Speaker: Dr. Mary Gehring - Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology - Dept. of Biology

 

Title: Epigenetic Reprogramming During Plant Reproduction

 

Abstract:

01/28/14

(Tues)

4:00 PM

8 Mueller

Biology Seminar Series

 

Speaker: Dr. Carolin Frank - University of California, Merced - School of Natural Sciences

 

Title: Nitrogen-Fixing Bacterial Endosymbioses in the Above-Ground Tissues of Subalpine Conifers

 

Abstract:

01/29/14

(Wed)

4:00 PM

501 Wartik

Genomics Seminar

 

Speaker: Dr. David Ardell - University of California, Merced - School of Natural Sciences

 

Title: The tRNA-interaction Network: Evolutionary Molecular Systems Biology and Applications to Deep Phylogeny

 

Abstract:

02/03/14

(Mon)

12:10 PM

108 Wartik

HUCK INSTITUTE LECTURE - Plant Biology

 

Speaker: Dr. Hong Ma - Penn State University - Dept. of Biology

 

Title: Functional and Molecular Evolutionary Analyses of bHLH Proteins Important for Anther and Pollen Development

 

Abstract:

02/18/14

(Tues)

4:00 PM

8 Mueller

Biology Seminar Series

 

Speaker: Dr. Mark Martindale - University of Florida – Whitney Laboratory for Marine Bioscience

 

Title: Radical Changes in Early Animal Evolution: How We Pulled Our Heads Out of Our Rears

 

Abstract:

03/05/14

(Wed)

12:10 PM

317 Mueller

Primary IMEG Seminar

 

Speaker: Dr. Mónica Medina - Penn State University - Dept. of Biology

 

Title: Elucidating Evolutionary Origins of Metazoan Biomineralization

 

Abstract:

Homology is a central concept in biology.  Defining homology based on organismal traits and coupling it with genetic variation remains challenging.  The challenge arises from the observation that in certain cases similar anatomical structures are not built using similar molecular processes.  While in other instances anatomically distinct structures in distantly related species arise through shared molecular interactions.  There has been a debate in the literature on whether biomineralization evolved once (homology) or multiple times (de novo) across metazoan phyla.  We are trying to fill phylogenetic gaps in our understanding of the process by conducting comparative transcriptomic and proteomic analyses of underrepresented taxa such as cnidarians and molluscs.  Our results have revealed a core biomineralization-related toolkit shared across metazoans.  However this toolkit is only conserved in some universal aspects of the process with multiple species-specific innovations across lineages.


 03/26/14

(Wed)

12:10 PM

317 Mueller

 

Primary IMEG Seminar

 

Speaker: Dr. Ruriko Yoshida - University of Kentucky - Dept. of Statistics

 

Title: kdetrees: Nonparametric Estimation of Phylogenetic Tree Distributions

 

Abstract:

While the majority of gene histories found in a clade of organisms are expected to be generated by a common process (e.g. the coalescent process), it is well-known that numerous other coexisting processes (e.g. horizontal gene transfers, gene duplication and subsequent neofunctionalization) will cause some genes to exhibit a history quite distinct from those of the majority of genes. Such "outlying" gene trees are considered to be biologically interesting and identifying these genes has become an important problem in phylogenetics. We propose and implement kdetrees, a nonparametric method of estimating distributions of phylogenetic trees, with the goal of identifying trees which are significantly different from the rest of the trees in the sample. Our approach mimics the common statistical technique of kernel density estimation, using tree distances to define kernels. In contrast to parametric models, such as the coalescent, nonparametric approaches avoid the problem of model mis-specification, which leads to potentially unreliable results. Our method demonstrated significantly faster computational time, while suffering only a small penalty to classification accuracy, as compared to a recently published method. We also applied our method to a data set of Apicomplexa genes, as well as a set of Epichlo\"e genes, fungi symbiotic with grasses. In the case of the Apicomlexa, kdetrees identified several unreliable sequences which had escaped previous detection, as well as gene indepentenly reported as a probably case of horizontal gene transfer. Our method for estimating tree distributions is implemented as the R package, kdetrees, and is available for download from CRAN.


04/02/14

(Wed)

12:10 PM

317 Mueller

Primary IMEG Seminar

 

Speaker: Dr. Zhenguo Zhang – Penn State University – Dept. of Biology (Nei)

 

Title: Why have the Mexican cavefish become blind?

 

Abstract:

The Mexican cavefish Astyanax mexicanus is an excellent model for studying phenotypic evolution. The fish has evolved many remarkable traits since its separation from its surface conspecific more than one million years ago. Moreover, hybrids of these two conspecifics are fertile, so traits can be studied using traditional genetic methods. Among the traits, blindness and albinism are most conspicuous. It has been hotly debated why the cavefish have lost their eyes – an outcome of positive selection or accumulation of disruptive mutations in eye loci which are neutral in cave environment. In this talk, I will review the relevant studies and conclude that the available data are more consistent with neutral evolution while the arguments for positive selection are often weak. Finally, I will present some results by analyzing latest RNA and genomic sequences of the cavefish, which provides new insights into the cavefish evolution.

References:

1. W. R. Jeffery, Regressive evolution in Astyanax cavefish. Annu Rev Genet 43, 25-47 (2009).

2. H. Wilkens, in Evolutionary Biology. (Springer US, 1988), vol. 23, pp. 271-367.

3. N. Rohner, D. F. Jarosz, J. E. Kowalko, M. Yoshizawa, W. R. Jeffery, R. L. Borowsky, S. Lindquist, C. J. Tabin, Cryptic variation in morphological evolution: HSP90 as a capacitor for loss of eyes in cavefish. Science 342, 1372-1375 (2013).

04/14/14

(Mon)

4:00 PM

112 Borland

HUCK INSTITUTE LECTURE - Ecology

 

Speaker: Dr. Rachel Whitaker – University of Illinois – Dept. of Microbiology

 

Title: Population Genetics and Genomics of Microbial Evolution

 

Abstract:

04/24/14

(Thurs)

11:00 AM

W203 MSC

HUCK INSTITUTE LECTURE - Infectious Disease Dynamics

 

Speaker: Dr. Deborah Gordon – Stanford University – Dept. of Biology

 

Title: Ants and the Evolution of Collective Behavior

 

Abstract:

04/28/14

(Mon)

4:00 PM

112 Borland

HUCK INSTITUTE LECTURE - Ecology

 

Speaker: Dr. Fred Allendorf – University of Montana – Dept. of Biological Sciences

 

Title: Human Induced Evolution caused by Unnatural Selection through Harvest of Wild Animals

 

Abstract: