A Biology Primer Part VI: Evolution and Forensic Biology

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A Biology PrimerPart VI Evolution and Forensic
Biology

• Vasileios Hatzivassiloglou
• University of Texas at Dallas

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Yeast microarray experiment

• Watch an animation explaining comparative
  microarray experiments at http//www.bio.davidson.
  edu/Courses/genomics/chip/chip.html

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Microarray output

• Genes (rows) vs. usually multiple comparisons and
  experimental conditions (columns)
• Experimental conditions can be given
  (healthy/diseased specimens) or directed
• Directed experimental conditions include
• genetic manipulation (gene knock-out)
• environmental changes (temperature, nutrition)

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Microarray output matrix

• Can we use this to infer network topology and/or
  actions?

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We have covered so far

• Biological classification
• Organisms, tissues, cells and organelles
• Cell, protein, DNA, RNA function, structure, and
  form
• DNA replication and organism reproduction
• Gene expression and its regulation
• Regulatory networks
• DNA microarrays

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Evolution principles

• Common ancestor
• abiogenesis or design?
• Inheritance of traits via mutation of germ cells
  (cf. mutation of somatic cells)
• Natural selection

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Evidence for evolution

• A central part of modern biology
• Supported by
• morphological evidence (fossil record) e.g., can
  trace the origins of the modern horse through
  several hundred species
• comparative anatomy (homologous organs)
• geographical distribution
• genetic evidence (DNA differences between
  organisms orthologous genes)

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Evolution timeline

• Earth forms (4.5 billion years ago)
• Earth acquires solid crust (4.1 by)
• First life form, self-replicating RNA (4 by) no
  oxygen in the atmosphere
• First bacteria and archaea (3.9 by)
• Photosynthesis in bacteria (3.5 by)
• First eukaryotes (2.1 by)
• Sexual reproduction (1.2 by)

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Evolution timeline, part II

• First multicellular organisms (algae and
  seaweeds, 1 by)
• Sponges, jellyfish, worms (600 my)
• First fish (500 my)
• First plants on land (475 my)
• Arthropods on land (450 my)
• First insects (400 my)
• Seeds in plants, amphibians (350 my)
• Pangaea, First reptiles (300 my)

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Evolution timeline, part III

• Crocodiles, first dinosaurs (250 my)
• Giant dinosaurs (150 my)
• First flowers (130 my)
• First ancenstor of mice and humans (100 my)
• Dinosaurs extinct, mammals dominate (65 my)
• First primates (55 my)

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Evolution timeline, part IV

• Earliest humans (homo habilis, erectus 2 my)
• Homo sapiens (140,000 years ago)
• Population reaches 5 million 11,000 years ago
• 150 million 2,000 years ago
• 6 billion 7 years ago
• 6.78 billion as of 16 September 2009
• Projected 9 billion by 2040

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Interactive evolution timeline

• Online at http//www.johnkyrk.com/evolution.swf

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A familiar organism

• Kingdom Animalia
• Phylum Chordata
• Subphylum Vertebrata
• Class Mammalia
• Order Primates
• Suborder Anthropoidea
• Superfamily Hominoidea
• Family Hominidae
• Genus Homo
• Species Homo sapiens
• Subspecies Homo sapiens sapiens

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Human migration

• Based on
• fossil record
• study of mtDNA (mitochondrial DNA)
• mtDNA better suited to tracking generations
• more mutations
• more copies
• retrievable from bone and teeth
• inherited only through the mother

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Identification through mtDNA
Stone AC, Starrs JE, Stoneking, M. Mitochondrial
DNA analysis of the presumptive remains of Jesse
James. J of Forensic Sci 2001 46(1)173176.
Jesse James (1847-1882) Notorious outlaw in
Missouri