Reconstructing the evolutionary history of species radiations – the impact of hybridisation Rob Smissen with contributions from Ilse Breitwieser, Leon.

Reconstructing the evolutionary history of species radiations – the impact of hybridisation

Rob Smissenwith contributions from Ilse Breitwieser, Leon Perrie,

Lara Shepherd, Peter Heenan and others ...

Leonard Cockayne HH Allan

“It is quite possible that no other natural area in the world has as great a number of genera whose definition of species is as badly confused by hybrid swarms”

1964. Bulletin of the Torrey Botanical Club 91: 114-140.

Pierre Dansereau

“The most that can be said about natural hybridisation in the New Zealand flora is that it is well attested in a few genera and is probable in others.”

J.B. Hair 1966N.Z. J. Bot. 4: 559-595.

Helichrysum lanceolatumAnaphalioides bellidioides

Helichrysum lanceolatum x Anaphalioides bellidioides

F1

BC1 BC1

F1BC1

P1

P1

Principal components analysis of AFLP data for mixed population

P. lessoniihoupara

coastal five-finger

P. crassifoliushoroeka

lancewood

P. crassifolius x P. lessonii

Pseudopanax and hybridisation (Perrie and Shepherd)

Backcross toBackcross to F1 F2

AFLP – NEWHYBRIDS analysis

Phormium (Harakeke: New Zealand flax)

P. tenax

P. cookianum

F1 hybrid

P. tenaxP. cookianum

Okiwi Bay

Structure estimates of ancestry from AFLP data

seed pods of typical Phormium and those of Okiwi Bay P. tenax

A contemporary biosystematic view

• Many hybrids well documented, few dismissed

• Geneflow among species seems limited overall

• Neo-allopolyploidy is well evidenced

• Homoploid hybrid species not yet demonstrated

See also, Pelser et al. American Journal of Botany 97(5): 856–873. 2010.

Asplenium polyploid evolution

Pachycladon

Arabidopsis

Pachycladon

Pachycladon

Brassica

Simplified low-copy nuclear gene-treenon-monophyly of duplicated gene copies

Raoulia alliance 2n=28+

Anaphalioides

Rachelia

Leucogenes

Ewartia

Raoulia Helichrysum

Craspedia 2n=22+

Allopolyploidy followed by aneuploid reduction?

Summary – hybridisation in the NZ flroa

•Contemporary hybridisation frequent

•Contemporary gene-flow among species is limited

•Aallopolyploid speciation important in some groups

•Paleo-allo-polyploidy in species rich groups

•Not certain how important homoploid hybrid speciation and introgression have been in species radiations

Acknowledgements

• Ilse Breitwieser & fellow symposium speakers• Mercè Galbany-Casals• NZPRN members• Leon Perrie and Lara Shepherd (for Asplenium and

Pseudopanax)• Peter Heenan (Pachycladon)