Phylogeny
Learning Objectives:
What is evolution and phylogeny?
Evolution and microbial phylogeny
How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
Torsten Thomas
t.thomas@unsw.edu.au
Learning Objectives:
What is evolution and phylogeny?
How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
Evolution & Phylogeny
Evolution: the process by which organisms become distinct from their ancestors.
Phylogeny: the study of relationships between groups of organisms based on shared characteristics - this can give clues to estimate the course of evolution.
?
1
Microbiology
• Types – bacteria, archaea, eucarya (diversity)
• Structure – Gram +ve, Gram –ve, peptidoglycan, rod, cocci
• Metabolism – autotroph, heterotroph, phototroph, carbon, nitrogen
• Physiology – macromolecular synthesis, growth responses, adaptation
• Ecology – environments & ecosystems, interactions, microbial processes
• Evolution – how, why, when
"Nothing in Biology Makes Sense Except in the Light of Evolution"
Christian Theodosius Dobzhansky, 1973
Learning Objectives:
Inferring evolution from phenotype
What is evolution and phylogeny?
Grouping present-day life according to physical characteristics... How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
…to “guess” at evolution.
2
Classical criteria
•
Cell type:
e.g. nucleus, cell shape
•
Level of organisation:
e.g. solitary/colonial unicellular or multicellular.
•
Nutritional type:
e.g. ingestive nutrition or photoautotrophic.
Problem:
No universal criteria for all organisms
16S/18S rRNA gene sequences are useful for phylogeny because:
Modern phylogeny:
Based on characteristics that are informative and shared by all living organisms…proteins & DNA
Molecular phylogeny
Microbial isolate
Extract genomic DNA and/or RNA
•
•
What is evolution and phylogeny?
Evolution and microbial phylogeny
How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
Torsten Thomas
t.thomas@unsw.edu.au
Learning Objectives:
What is evolution and phylogeny?
How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
Evolution & Phylogeny
Evolution: the process by which organisms become distinct from their ancestors.
Phylogeny: the study of relationships between groups of organisms based on shared characteristics - this can give clues to estimate the course of evolution.
?
1
Microbiology
• Types – bacteria, archaea, eucarya (diversity)
• Structure – Gram +ve, Gram –ve, peptidoglycan, rod, cocci
• Metabolism – autotroph, heterotroph, phototroph, carbon, nitrogen
• Physiology – macromolecular synthesis, growth responses, adaptation
• Ecology – environments & ecosystems, interactions, microbial processes
• Evolution – how, why, when
"Nothing in Biology Makes Sense Except in the Light of Evolution"
Christian Theodosius Dobzhansky, 1973
Learning Objectives:
Inferring evolution from phenotype
What is evolution and phylogeny?
Grouping present-day life according to physical characteristics... How do we measure or analyse it?
What are the underlying mechanisms?
How did it all start?
…to “guess” at evolution.
2
Classical criteria
•
Cell type:
e.g. nucleus, cell shape
•
Level of organisation:
e.g. solitary/colonial unicellular or multicellular.
•
Nutritional type:
e.g. ingestive nutrition or photoautotrophic.
Problem:
No universal criteria for all organisms
16S/18S rRNA gene sequences are useful for phylogeny because:
Modern phylogeny:
Based on characteristics that are informative and shared by all living organisms…proteins & DNA
Molecular phylogeny
Microbial isolate
Extract genomic DNA and/or RNA
•
•