|Date & Time||Location||Title||Speaker|
|Feb 4, 3:30 pm||1400 MSC||Transposable elements and the evolution of the very large genomes of conifers
See abstract below.
|Claudio Casola, Assistant Professor of Forest Genomics, Department of Ecosystem Science and Management, Texas A&M University|
|Feb 18, 3:30 pm||1400 MSC||The evolution of Darwin’s finches and their beaks revealed by genome sequencing
See abstract below.
|Leif Andersson, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden, and Department Veterinary Integrative Biosciences, Texas A&M University|
|Mar 4, 3:30 pm||1400 MSC||Conservation scaling from neighborhoods to landscapes
See abstract below
|Lee Fitzgerald, Professor, Wildlife and Fisheries Sciences|
|Mar 11, 3:30 pm||1400 MSC||A taste for the beautiful: Darwin y el papel evolutivo de las decisiones de apareamiento [in Spanish]||Gil Rosenthal, Professor, EEB program, Department of Biology, Texas A&M University|
|April 1, 3:30 pm||1400 MSC||Phylogenomics of the cat family provides insights into interspecific hybridization and the mechanistic basis for Haldane’s Rule||William Murphy, Department of Veterinary Integrative Biosciences, Texas A&M University|
|May 6, 3:30 pm||1400 MSC||Drivers of West Nile virus transmission: Do co-circulating parasites matter?||Gabriel Hamer, Assistant Professor, Department of Entomology, Texas A&M University|
Seminar Abstracts and Speaker Bios
Wednesday, February 4, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
Transposable elements and the evolution of the very large genomes of conifers
Presented by Dr. Claudio Casola, Assistant Professor of Forest Genomics, Department of Ecosystem Science and Management, Texas A&M University
Abstract: The majority of eukaryotic genomes is riddled with transposable elements (TEs), a group of ‘parasitic’ repetitive sequences capable of mobilizing and amplifying themselves in the host nuclear DNA. The accumulation of TE copies is a major driver of genome expansion in animals and plants, where up to 80% of the DNA in the nucleus can be occupied by TEs. One of the key determinants of TEs success in eukaryotes is their ability to jump across species boundaries and invade new taxa. Several of these TE horizontal transfers have been documented within vertebrates, insects and angiosperms, but no trans-kingdom horizontal transfer event has been described thus far. In this talk, I will present evidence supporting the transfer to conifers of a TE group called Penelope-like elements, or PLEs, which was previously known to occur only in animals. Phylogenetic analyses suggest that PLEs have been transferred to a common ancestor of all conifers from a yet unidentified group of arthropods around 300 million years ago. This and other TE horizontal transfers could have significantly contributed to the genome expansion that characterized the evolution of early conifers and is reflected in the current exceptionally high DNA content of this group of seed plants.
About this speaker: Dr. Claudio Casola leads the Forest Genomics lab in the Department of Ecosystem Science & Management. Research in the Casola’s lab blends computational and molecular biology approaches, and is mainly focused on the evolution of genes and genomes in gymnosperms, the genetic basis of adaptation in loblolly pine and other pine trees, and the application of genomic tools to tree improvement programs in the Southeastern United States.
Wednesday, February 18, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
The evolution of Darwin’s finches and their beaks revealed by genome sequencing
Presented by Prof. Leif Andersson, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden, and Department Veterinary Integrative Biosciences, Texas A&M University
Abstract: Darwin’s finches on Galápagos Islands are a classic example of an adaptive radiation. The evolution of this group of birds is characterized by rapid ecological diversification and speciation, and adaptation to an unstable and challenging environment, resulting in striking diversity in morphology (beak type, plumage and body size), feeding ecology and behavior. However, we know little about how processes such as selection and gene flow have shaped patterns of polymorphism and divergence across the genomes of these species to produce this astonishing phenotypic variation. We have performed whole genome sequencing of 120 birds that include all 14 currently recognized species of Darwin’s finches, the closely related Cocos island finch and two closely related tanagers from Barbados. The reads were aligned against a draft genome assembly of the Medium ground finch (Geospiza fortis), and ~ 43 million single nucleotide variants across all species. These data have been used to estimate nucleotide diversities, effective population sizes, species divergence times and phylogenetic relationships. The results reveal a large number of trans-species polymorphism, and highlight the importance of historical and ongoing gene flow in their evolution. A phylogeny based on whole genomes allows us to propose a revised taxonomy for the group. We also identify loci with strong signatures of selection that have contributed to the phenotypic diversification of the Darwin’s finches.
About this speaker: Leif Andersson is a professor in Functional Genomics at Uppsala University and guest professor in Molecular Animal Genetics at the Swedish University of Agricultural Sciences in Uppsala.
His research group did pioneering work using domestic animals for genetic dissection of monogenic and multifactorial traits. Main research project includes genetic analysis of divergent intercrosses in chicken, horses and pigs. Andersson’s group describe the genes and mutations affecting a certain trait and study the mechanism of the genes and regulatory elements affected by the mutations.
Wednesday, March 4, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
Conservation Scaling From Neighborhoods to Landscapes
Presented by Lee Fitzgerald, Professor, Department of Wildlife and Fisheries Sciences, Texas A&M University
Abstract: A central question in conservation science is “What allows a species to persist and conversely, what causes it to disappear?” The answer to the ecological side of the question depends on factors such as species’ life history and behavioral constraints, its role in ecological communities, and its sensitivity to landscape change. The relative importance of these sorts of ecological processes varies with scale. The conservation answer depends on the match between ecological scaling and conservation scaling: the extent to which conservation measures are effective at multiple spatial and temporal scales. I will discuss how most paradigms in conservation, for example sustainable use, ecotourism, and endangered species conservation are confronted with challenges related to scaling and mismatch. In particular, our research on a micro-endemic habitat specialist, the Dunes Sagebrush Lizard (Sceloporus arenicolus), lends insight to challenges of conservation scaling. Meticulous ecological studies reveal how population dynamics in these lizards scale from local neighborhoods of interacting individuals up to the distribution of the species across its geographic range. Moreover, the condition and configuration of irreplaceable landforms are directly linked to population vital rates, neighborhood vitality, and persistence of populations. The Mescalero Dune Ecosystem, where these lizards and other endemic species exist, overlies the Permian Basin, a region beset with increasing and extensive fragmentation from oil and gas development. Landscape fragmentation lands a double whammy by disrupting both the geomorphologic processes that maintain dunes and the diffusion-dispersal dynamics that connect lizard neighborhoods. Conservation measures are (sort of) in place for the Dunes Sagebrush Lizard that call for localized habitat protection. However, the extent of these measures does not match the dynamics of ecological scaling in this system and probably will not confront the higher-level problem of fragmentation that drives species disappearance. The mismatch between conservation scaling and ecological scaling is a pervasive challenge to achieving biodiversity conservation. Conservation scientists and practitioners might benefit from embracing the realities of conservation scaling, and taking advantage of scaling opportunities and planning for the scaling limits of conservation interventions.
About this speaker: Dr. Fitzgerald’s program is best described as evolutionary ecology and conservation biology of amphibians and reptiles. He uses reptiles and amphibians as study systems at the community and landscape level to address the general questions, “What are mechanisms influencing the fit between organism and environment?”, and “How do community-level processes influence species persistence and distribution of species across the landscape?” This program addresses various conservation issues, for example, habitat requirements of single species, determinants of local and regional diversity, or mechanisms determining the fate of invasive and native species.
Wednesday, March 11, 3:30-4:30 pm, Room 2504 Memorial Student Center (MSC)
A taste for the beautiful: Darwin y el papel evolutivo de las decisiones de apareamiento [in Spanish]
Presented by Gil Rosenthal, Professor, EEB program, Department of Biology, Texas A&M University
Wednesday, April 1, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
Phylogenomics of the cat family provides insights into interspecific hybridization and the mechanistic basis for Haldane’s Rule
Presented by William Murphy, Professor, Department of Veterinary Integrative Biosciences, Texas A&M University
Abstract: Interspecies hybridization has been recently recognized as potentially common in wild animals, but the extent to which it shapes modern genomes is still poorly understood. Distinguishing historical hybridization events from other processes leading to phylogenetic discordance among different genetic markers requires a well-resolved species tree that considers all modes of inheritance, the influence of sex-biased dispersal, and overcomes systematic problems due to rapid lineage diversification by sampling large genomic character sets. We assessed genome-wide phylogenetic variation within all living members of a diverse mammalian family, Felidae (cats), using the Illumina SNP array and whole genome sequencing. I will present the first robust phylogeny and timetree that accounts for unique maternal, paternal, and biparental evolutionary histories in the ancestry of living cats. Genome wide phylogenetic scans identified signatures of discordance that are abundant in the genomes of felids, and have been driven by ancestral introgression. Several feline interspecies hybrids also represent popular cat breeds worldwide, and uniformly exhibit hybrid male-limited sterility (Haldane’s Rule). I will also discuss advances in our mapping of hybrid male sterility genes in controlled crosses from multiple interspecies breeds, as a novel model system for understanding the mechanistic basis for Haldane’s Rule. Our results highlight the mosaic origin of modern felid genomes and the influence of sex chromosomes in post-speciation gene flow.
About this speaker:
Wednesday, May 6, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
Drivers of West Nile virus transmission: Do co-circulating parasites matter?
Presented by Gabriel Hamer, Assistant Professor, Department of Entomology, Texas A&M University
Abstract: West Nile virus (WNV) is the most widely distributed zoonotic arthropod-borne virus and has caused an estimated 780,000 human illnesses and over 1,500 deaths in the U.S. since its introduction to New York in 1999. WNV is maintained in an enzootic transmission cycle between Culex mosquitoes and birds, and the efficiency of this virus to circulate in nature is driven by multiple ecological factors. These factors have been modeled in a quantitative framework called vectorial capacity, which determines the daily rate at which future infections arise from a currently infective case. This talk will outline the diverse drivers of arbovirus transmission and focus on the potential for co-circulating parasites and pathogens to have important consequences for for human and animal health.
About this speaker: Dr. Hamer’s research broadly investigates the ecology of infectious diseases of humans, wild animals, and domestic animals, with particular attention to those transmitted by arthropod vectors (e.g. mosquitoes, ticks, midges). He has focused primarily on vector-host interactions that lead to parasite amplification and increased disease risk. He utilizes a multidisciplinary approach to studying these complex disease systems, including molecular biology, landscape epidemiology, eco-immunology and ecological modeling. A goal of Dr. Hamer’s research is to elucidate mechanisms of transmission across space and time that facilitate ecological management of diseases with effective intervention and preventative strategies. His current research focuses on West Nile virus, dengue, haemosporidian parasites, and filarioid nematodes.