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?