Past Events

  • 2013 Nov 20

    Origins Forum - "The meaning of stromatolites"

    4:00pm to 5:00pm

    Location: 

    Geological Museum, Haller Hall (Room 102), 24 Oxford Street

    Tanja Bosak
    Dept. of Earth, Atmospheric & Planetary Sciences
    Massachusetts Institute of Technology

    Mineral precipitation, sedimentation and microbial activity have shaped landscapes in coastal environments for nearly 3.5 billion years, forming stromatolites and other sedimentary structures.  The shapes and textures of these structures may record  evolutionary and chemical changes during the first  80% of Earth's sedimentary history. However, as complex products of physical processes, microbial ...

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  • 2013 Nov 14

    Chalk Talk - "Oligomer assisted non-enzymatic RNA polymerization"

    9:00am to 10:00am

    Location: 

    Naito Laboratory, Room 205 12 Oxford Street

    Noam Prywes
    Graduate Student - Dept. of Chemistry & Chemical Biology (Szostak Lab)

    A central tenet of the RNA world is that RNA polymerases could replicate themselves.  Over the last 20 years, RNA-dependent RNA polymerases have been evolved that can copy RNA sequences longer than themselves.  The development of these polymerases required many rounds of selection and amplification.  Since amplification would have required a polymerase there appears to be a paradox.

    Non-enzymatic polymerization has been proposed as a solution to this paradox....

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  • 2013 Oct 16

    Origins Forum - "RNA-Mediated Epigenetics and Extreme Genome Architectures in the Ciliate Oxytricha"

    4:00pm to 5:00pm

    Location: 

    Geological Museum, Haller Hall (Room 102), 24 Oxford Street

    Laura Landweber  
    Dept. of Ecology & Evolutionary Biology
    Princeton University

    The unicellular eukaryote Oxytricha trifallax has an extremely dynamic pair of genomes, with massive DNA rearrangements producing a highly fragmented, somatic genome from a germline genome roughly twenty times its sequence complexity. During development, Oxytricha eliminates nearly all its noncoding DNA, including all its transposons, and rearranges the ~225,000 remaining DNA pieces to produce functional genes. In the precursor, germline genome, the scattered segments of different genes...

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  • 2013 Oct 03

    Chalk Talk - "Going to Extremes: Ultra-High Pressure Studies of Planetary Materials"

    9:00am to 10:00am

    Location: 

    Naito Laboratory, Room 205 12 Oxford Street

    Dylan K. Spaulding
    Origins Postdoctoral Fellow - Department of Earth & Planetary Sciences (Stewart Lab)

    Exploring materials under extreme conditions of pressure and temperature is critical for understanding planetary formation, evolution and structure. Impact processes on planetary surfaces also play an important role in shaping the planetary environment and setting the stage for the possible sustenance of life. Here, I will discuss how static compression and shock wave experiments can be used to probe conditions from a few gigapascals to terapascal regimes and from...

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  • 2013 Sep 18

    Combinatorial Chemistry in the Prebiotic Environment

    4:00pm to 5:00pm

    Location: 

    Geological Museum, Haller Hall (Room 102), 24 Oxford Street

    David Deamer
    Department of Biomolecular Engineering
    University of California, Santa Cruz

    The pathway leading to the origin of life presumably included a process by which polymers were synthesized abiotically from simpler compounds on the early Earth, then encapsulated to form protocells. Previous studies have reported that mineral surfaces can concentrate and organize activated mononucleotides, thereby promoting their polymerization into RNA-like molecules. However, a plausible prebiotic activation mechanism has not been established, and minerals cannot form cellular...

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  • 2013 May 15

    Where are the boundaries of the Habitable Zone?

    4:00pm

    Location: 

    Geo Museum, 24 Oxford Street, Haller Hall, Rm. 102, Cambridge, MA

    James Kasting (Professor of Geosciences & Meteorology - Pennsylvania State University) 

    NASA’s Kepler Space Telescope has been in operation for more than 4 years, and its dataset on transiting exoplanets is becoming more and more complete. It is now becoming feasible to make estimates for Eta_Earth—the fraction of Sun-like stars that have at least one rocky planet within their habitable zone. The habitable zone, as conventionally defined, is the region around a star where liquid water can exist on a planet’s surface....

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  • 2013 May 02

    A Possible Mechanism for Methane Outgassing in Water Planets

    9:00am

    Location: 

    Biological Laboratories, 16 Divinity Ave., BL Room #1075, Cambridge, MA

    Amit Levi (Harvard-Smithsonian Center for Astrophysics)

    Planets with a substantial ice mass fraction, covering their entire surface, and lacking an H/He atmosphere are commonly referred to as water planets. These planets, first suggested as a Gedanken experiment by Kuchner (2003) and Leger et.al. (2004) based on the large variety among discovered extra-solar systems, have become an astronomical fact with the large number of low planetary mean densities as measured by the Kepler mission. Water planets appear to be relatively common, and being a novel type of planet...

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  • 2013 Apr 17

    Physical and Chemical Models for the Origin of Biological Homochirality

    4:00pm

    Location: 

    Geo Museum, 24 Oxford Street, Haller Hall, Rm. 102, Cambridge, MA

    Donna Blackmond (Professor of Chemistry - The Scripps Research Institute)

    The property of chirality has fascinated scientists and laymen alike since Pasteur’s first painstaking separation of the enantiomorphic crystals of a tartrate salt over 150 years ago. Chiral molecules – nonsuperimposable forms that are mirror images of one another, as are left and right hands – in living organisms in Nature exist almost exclusively as single enantiomers, as exemplified by D-sugars and L-amino acids. Single chirality is critical for molecular recognition and...

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  • 2013 Apr 04

    Constraining the global sulfur cycle at the enzymatic scale

    9:00am

    Location: 

    Biological Laboratories, 16 Divinity Ave., BL Room #1075, Cambridge, MA

    Wil Leavitt (Dept. of Earth & Planetary Sciences/Johnston Lab)

    The sedimentary sulfur isotope record is an integrator of biochemical processes, the most quantitatively important of which is microbial sulfate reduction (MSR). Interpretations of the sedimentary sulfur isotope record rely largely on our understanding of the fractionation associated with MSR. This has been empirically determined by numerous cellular-scale studies [1, 2, 3]. Still, a mechanistic understanding for the controls on this fractionation has proven elusive. Moreover, metabolic...

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  • 2013 Mar 13

    Mineral Surfaces as Evolutionary Stress and Prebiotic Enzymes for Protocell Survival and Trans-Membrane Energy Transduction

    4:00pm

    Location: 

    Geo Museum, 24 Oxford Street, Haller Hall, Rm. 102, Cambridge, MA

    Nita Sahai (University of Akron - Dept. of Polymer Science)

    Minerals, because of their reactivity and ubiquity, likely contributed to the transformation from prebiotic geochemistry to biochemistry. We propose two central hypothesis: that mineral surfaces acted as (1) an “evolutionary selection stress” in selecting lipid or amphiphile membrane compositions that were stable (survival of the fittest protocells) and (2) as “prebiotic enzymes” for photocatalyzed trans-membrane energy transduction in the emergence of metabolism. We use phospholipid and...

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