2 items with the tag “molecular phylogeny

  • Genomic Relationships Among Basal Metazoans
    NAI 2009 Massachusetts Institute of Technology Annual Report

    The origin of animals, and animal complexity, requires an accurate and precise understanding of both the phylogenetic interrelationship among the earliest evolved animals and the paleoecological milieu within which they evolved. Our work has shown that sponges are indeed the first animals that evolved that still have living descendants, and that sponges are not a natural group. Instead, some sponges are more closely related to more complex animals like humans and jellyfish than they are to other sponges (e.g., bath sponges). This suggests that the origins of animal complexity is rooted in sponge paleobiology, and that the earliest animals were designed to eat bacteria and organic carbon instead of other large eukaryotes like other sponges or plants.

    ROADMAP OBJECTIVES: 4.2
  • Genomic Relationships Among Basal Metazoans
    NAI 2010 Massachusetts Institute of Technology Annual Report

    Understanding the origins of animals (“Metazoa”) and the advent of metazoan complexity requires a proper understanding of the interrelationships among the living forms. To properly place animals like sponges and jellyfish into the tree of life, we have taken a multi-faceted approach using two different kinds of molecular data: traditional sequence-based molecular phylogenetics, and a new type of binary data, the presence or absence of specific microRNAs (short ~22 nucleotide non-coding RNA genes). Both data sets suggest that sponges are paraphyletic: some sponges are more closely related to jellyfish and humans than they are to other sponges (e.g., bath sponges). These results suggest that the last common ancestor of all living animals was organized like a true sponge, and thus our origins as complex animals lies within sponge biology.

    ROADMAP OBJECTIVES: 4.2