Mammalian Evolution Using IRBP Gene

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Mammalian Evolution Using IRBP Gene
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Goal

• To provide a problem space wherein students can
  use sequence data using a slowly evolving genes
  to resolve deep-level divergences within and
  among mammalian groups.
• To illustrate the explanatory powers of
  (molecular) phylogenetics for biology.

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Problems with deep-level divergences

• Mitochondrial markers are too fast evolving to
  resolve divergences of more than gt50 millions
  years.
• - Data sets often beset by saturation
  (homoplasy) and trees often suffer from long
  branch attractions.

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Some Potential Questions

• Does the major grouping of mammals reflect
  biogeographic history?
• Does molecular phylogeny reflect present
  (worldwide or local) distribution?
• Are marsupials monophyletic relative to eutherian
  mammals?
• Are rodents monophyletic?
• To what groups of mammals whales and dolphins are
  most related to?

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Opportunities for students

• Provides students to pose many other questions
  and generate many hypotheses.
• Investigate the concept of HOMOLOGY in both
  molecular and morphological (or behavioral,
  ecological ) data sets
• Test geographic events with character evolution.
• Allow students to view biodiversity (and
  conservation) in the context of evolution.

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IRBP exon 1(Interphotoreceptor Binding Protein)

• Single copy nuclear gene (currently the most
  widely used marker for mammalian phylogeny)
• Widely used to infer mammalian phylogeny
• Relative rate of mutation is slower than
  mitochondrial genes, thus, ideal marker to
  resolve deep-level divergences

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Phylogeny of placental mammals Murphy et al.
2001. Nature.294 2348-2351
Cetartiodactyla
Perissodactyla
Laurasiatheria
Carnivora
Pholidota
Chiroptera
Eulipotyphla
Rodentia
Glires
Lagomorpha
Euarchonta
Dermoptera
Scandentia
Primates
Pilosa
Xenarthra
Cingulata
Afrosoricida
Macroscelidea
Tubulidentata
Afrotheria
Sirenia
Hyracoidea
Proboscidea
Marsupialia
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Other Possibilities

• Using other genes, such as vonWillebrand and
  rag-1 genes to further illustrate the virtues of
  the scientific concept
• Testability,
• Repeatability,
• Congruence among independent data sets