PHYLOGENETICS OF THE GRASS FAMILY
(POACEAE)
Vishnu Mohanan
Supervisor: Dr. Trevor Hodkinson
WHY GRASSES?
Biodiversity
Over 9000 species
Pioneer species and establishment of ecosystems
Economic
70% of all food crop
Fuel
Construction
Paper
WHY PHYLOGENETICS?
How the group is organised
Improved resolution when used in conjunction with
geographical and morphological data.
Major diversification events
Eg: Emergence of woodiness in Bamboos
Resolution of taxonomic conflicts
Similar morphology, different group?
Plantae Angiosperm Monocot Poales Poaceae
OUR STUDY
Sequence grass DNA
Huge species number
Generic level analysis
Asymmetry in phylogenies
METHOD
PCR Cleanup
Extraction and purification
Electrophoresis gel
Amplification of gene region
using PCR
Collection and Storage
Cycle Sequencing
Cycle Sequencing cleanup
Fragment Analysis using Genetic Sequencer
Electrophoresis gel
Yes No
AGAROSE GEL ELECTROPHORESIS
Total DNA
AGAROSE GEL ELECTROPHORESIS
PCR Products
AGAROSE GEL ELECTROPHORESIS
ELECTROPHEROGRAM
SEQUENCES ATTAINED
18 sequences attained
12 Phylostachys species
2 Fargesia species
1 Pleoblastus species
ALIGNMENT
Aligned by eye in PAUP
PHYLOGENETIC TREE
Well resolved BEP clade
Bambuseae as a
monophyletic tribe
Olyreae sister to
Bambuseae
Pooideae sister to
Bambusoideae
BEP Clade
Bambusoideae
BAMBUSEAE
Separation in
geography
Temperate bamboos
Phylostachys
Fargesia
Pleoblastus
Paleotropical
Neotropical
COMPARING TREES
BEP Clade
Bambusoideae
DISCUSSION
Ancestral bamboo herbaceous or woody?
Woodiness has evolved independently number of times
According to the results, likely that ancestor herbaceous
Olyreae remained herbaceous
Bambuseae developed woodiness
Conflicts with published studies
Further sampling of Olyreae
DISCUSSION
Storage of plant material in liquid CTAB viable?
High degradation of DNA material
Hard to work with
Unreliable PCR amplification
ACKNOWLEDGEMENTS
Dr. Trevor Hodkinson
Postgraduates: Ruth, Muriel and Caoimhe
Trish!
Fellow ‘UREKA’ns
Dr. Daniel Kelly, Fiona Moloney and Dr. Martyn Linnie
Luke McNally, our fearless leader
Science Foundation Ireland
QUESTIONS?
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