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Molecular phylogenies

Molecular phylogenies. DNA sequence changes to: ATTGCT T TTC. Ancestral DNA sequence: ATTGCT A TTC. Mutations can create synapomorphies. Reversal to A at 7th position. DNA sequence changes to: ATTGCT T TTC. Ancestral DNA sequence: ATTGCT A TTC.

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Molecular phylogenies

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  1. Molecular phylogenies

  2. DNA sequence changes to: ATTGCTTTTC Ancestral DNA sequence: ATTGCTATTC Mutations can create synapomorphies

  3. Reversal to A at 7th position DNA sequence changes to: ATTGCTTTTC Ancestral DNA sequence: ATTGCTATTC Reversals (‘back mutations’) can remove synapomorphies

  4. rodhocetus

  5. mesonychid basilosaurus ambulocetus rodhocetus

  6. Molecular data used in phylogenetic analysis Immunological distance DNA-DNA hybridization Protein electrophoresis Restriction sites Amino acid sequences DNA sequences

  7. Molecular data used in phylogenetic analysis Immunological distance DNA-DNA hybridization Protein electrophoresis Restriction sites Amino acid sequences DNA sequences

  8. Molecular data used in phylogenetic analysis Restriction sites

  9. Molecular data used in phylogenetic analysis Immunological distance DNA-DNA hybridization Protein electrophoresis Restriction sites Amino acid sequences DNA sequences

  10. Tissues from which ancient DNA has been extracted Type of material Maximum age Mummies 5000yrs Bog bodies 7500yrs Feathers 130yrs Museum skins 140yrs Naturally preserved skins 10000yrs Bones 25000+yrs Amber insects ??? Herbaria specimens 118yrs Charred seeds & cobs 4500yrs Mummified seeds & embryos 44600yrs

  11. Molecular clocks All phylogenies assume evolutionary differences arise from mutational differences greater mutational differences = greater evolutionary distance

  12. Molecular clocks If molecular clock assumptions are true, Phylogeny could be inferred from overall similarity of spp If calibrated, could estimate actual time since taxa diverged

  13. Molecular clocks Relative rates Calibrated rates

  14. Molecular clocks Problems Clock rate differs for different taxonomic groups & nucleotide sequences Differences in DNA repair efficiency Differences in metabolic rates Differences in generation time?

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