"What's in a Name?"
Molecular Insights into Evolution & Population Biology at Memorial University

The "Species Problem"
       "Species" is used for
       an evolutionary unit (dynamic)
       a taxonomic unit (ideally, fixed)
                "Species are as many as were created in the beginning by the Infinite."
                     (Linnaeus, 1758)

   Study of evolution is exciting; study of taxonomy is dull (or worse)
          "I look at the term species, as one arbitrarily given for the sake of convenience
           to a set of individuals closely resembling each other...." (Darwin, 1859)

          The undergraduate species concept:
              "Why can't y'all just pick one name so I can memorize it and forget it?"
                   (A&M student, 1984)

A modern view: Systematics (the science of naming organisms) is dynamic
        Taxonomy is based on hypotheses of relationship:
               "A & B are more closely related to each other than either is to C"
              Relationships are simple: patterns of common ancestry
        Natural Classification will reflect these relationships (phylogeny)
        Nomenclature (scientific names) changes when hypotheses are modified


Why use molecules?

       How it Works : "Helix & Primer"  DNA Sequencing Service

         Molecules provide large data sets:
             Homo has 2 x 102 bones versus 3 x 10 nucleotide pairs
             Different genes provide complementary insights:
                   maternal mtDNA vs paternal Y-DNA
                   [except sometimes: sexing birds]

       Rules of molecular evolution are understood:
                Ts vs Tv  /  silent vs substitution  /  3rd vs 1st & 2nd
                Methods of Phylogeny Reconstruction are robust

      Molecules provide independent estimates of phylogeny
         Avoids a circular argument:
          Morphology, behaviour, and/or biogeography create classification,
               classification explains evolution of morphology etc.


What molecules tell us about ...

      Morphological evolution of antlers in New World Deer (Cervidae)
              All deer have antlers except Chinese water deer (Hydropotes)
                   => a separate subfamily (Hydropotinae) & the ancestral type
          But: Molecular analysis shows Hydropotes antlers lost secondarily
                    => part of the New World subfamily (Odocoileinae)
                          Antlers started big, got smaller
                                Neotropical deer are an independent radiation
                                "Spike antlers" are consequences of allometry

       Breeding behaviour in seals of the North Atlantic (Phocidae)
             Origins of substrate usage in pagophilic- vs terrestrial-breeding species
                  "Type" Harbour Seal (Phoca vitulina Linnaeus, 1758) breeds on land
                  "Greenland" Harp Seal (Phoca groenlandica) breeds on ice: Why?
         But: Molecular analysis shows that Harps & Hooded Seals (Cystophora) are close relatives
                    Harp seal = Pagophilus groenlandicus
                    => Pagophilic breeding is ancestral

      Biogeographic origins of Pacific codfish (Gadidae)
            All cod, haddock, & pollock were originally Gadus L., 1758
            Molecular analysis shows Pacific endemics are independent invasions
                 Tomcod (Micgrogadus spp.) includes Saffron Cod & Navaga (Eleginus spp)
                 Pacific Cod (Gadus macrocephalus) includes Greenland Cod
                 Alaska Pollock (Theragra chalcogramma) = G. chalcogrammus ? (Work in Progress)


What mitochondrial genomics tell us about population biology & evolution

       Genomics: the study of complete gene sets

       Marine Mitochondrial Genomics
            A whole-genome approach to population biology & systematics
                 with special reference to fisheries
            High-Resolution & Statistical confidence

      The "Out of Africa" hypothesis of human origins (Ingman et al. 2000)
             Origins of first settlers of Newfoundland (Pope, Marshall, & Carr 2004)

       The "Out of Newfoundland" hypothesis of harp seal origins (Work in Progress)
              Evolution of Phocid Seals
              Harp Seal population genomic structure


... and for something completely different
How to tell a Sea Monster: identifying the Fortune Bay "sea monster"

All text material © 2004 by Steven M. Carr: Details & Other Projects