Browsing by Subject "evolutionary biology"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Open Access
    Evolutionary biology
    (2014-09-29) Illing, Nicci; Muthama, M
    Charles Darwin’s hypothesis of evolution by natural selection or ‘descent with modification’ underlies all modern biology. It allows us to understand our genes, fight viruses, and understand the living and extinct biodiversity of our planet. This course will explore how our knowledge of evolution is important in our society today. A key question today is understanding how the morphology of animals has diversified, given the common set of genes that are found in vertebrate genomes. This question will be considered in the second lecture with a focus on the homeotic genes (or Hox genes) which are highly conserved master regulators of cell identity and morphology in animals. Moving to the plant kingdom, the second lecture will use African biomes as the focus for discussing the evolution of diversity, specifically the African savanna’s ‘underground forests’ will be described and analysed.
  • Thumbnail Image
    Item
    Open Access
    Protein sequences bound to mineral surfaces persist into deep time
    (2016) Demarchi, Beatrice; Ecker, Michaela; Kolska Horwitz, Liora; Chazan, Michael; Kröger, Roland; Thomas-Oates, Jane; Harding, John H; Cappellini, Enrico; Penkman, Kirsty; Collins, Matthew J
    Proteins persist longer in the fossil record than DNA, but the longevity, survival mechanisms and substrates remain contested. Here, we demonstrate the role of mineral binding in preserving the protein sequence in ostrich (Struthionidae) eggshell, including from the palaeontological sites of Laetoli (3.8 Ma) and Olduvai Gorge (1.3 Ma) in Tanzania. By tracking protein diagenesis back in time we find consistent patterns of preservation, demonstrating authenticity of the surviving sequences. Molecular dynamics simulations of struthiocalcin-1 and -2, the dominant proteins within the eggshell, reveal that distinct domains bind to the mineral surface. It is the domain with the strongest calculated binding energy to the calcite surface that is selectively preserved. Thermal age calculations demonstrate that the Laetoli and Olduvai peptides are 50 times older than any previously authenticated sequence (equivalent to ~16 Ma at a constant 10°C).