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Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterfly Astraptes Fulgerator

Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterfly Astraptes Fulgerator. In. Paul Hebert, Erin Penton, John Burns, Daniel Janzen & Winnie Hallwachs Proceedings of the National Academy of Sciences 2004 Content: Jan Critique: Emily. DNA Barcoding.

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Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterfly Astraptes Fulgerator

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  1. Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterfly Astraptes Fulgerator In Paul Hebert, Erin Penton, John Burns, Daniel Janzen & Winnie Hallwachs Proceedings of the National Academy of Sciences 2004 Content: Jan Critique: Emily

  2. DNA Barcoding What is it? ● Large scale screening of just a few reference genes for species ‘barcodes’. e.g. COI (Cytochrome C Oxidase 1) mtDNA • Two purposes: • Molecular classification of unknown individuals to identified taxa. • (e.g. the field barcoder) • 2) Discovery of previously unknown species. • (e.g. cryptic species)

  3. DNA Barcoding Is it anything really new? ………NO ………. BUT! Scale & Standardization ‘One gene fits all’

  4. DNA Barcoding However, ‘Barcoding’ is a bit of a misnomer… … not all individuals have the same ‘barcode’! Thus required that: Intraspecific variation << Interspecific variation

  5. DNA Barcoding For example in moths and birds it has been shown that: - Intraspecific sequence variation < 0.5% . - Interspecific sequence variation > 5%. Recognised sister taxa generally show > 3% sequence divergence. Thus the general rule that > 3% sequence divergence is indicative of separate species.

  6. Study Species • Described in 1775 • Single Species • Common • USA to Argentina • Near desert to rainforest Neotropical Skipper Butterfly Astraptes fulgerator

  7. Study Species However… • Diversity of Food Plants • Caterpillar Color Pattern • V. subtle differences in adult morphology. 6 – 7 Species??? Years more work…

  8. But wait…… ‘DNA barcoding’ is here!

  9. Methods • 484 museum specimens. • Data on food plant, caterpillar color pattern & adult morphology. • ‘legs away for DNA’ • Barcoding at Guelph: • Extraction • Amplification of 648bp COI region • Sequencing

  10. Methods • Sequences aligned. • Divergence measured with K-2-P distance model. • Displayed in neighbour joining tree.

  11. Results 10 Distinct Sequence Groups Close correspondence with other characteristics

  12. Key Points Branch lengths Intraspecific v Interspecific Other characters

  13. TRIGO & CELT > 3% Sequence Divergence Unique food plants Diverged ~ 2 & 4 mya Distinct Spp?

  14. FABOV, HIHAMP & INGCUP < 0.5% Sequence Divergence Host plants not exclusive Diverged < 0.5 mya ???Distinct Spp???

  15. Not one species BUT….. Conclusion A complex of 10 cryptic species!

  16. Conclusion • How many more such complexes are out there? • Crucial to our estimates of global biodiversity and extinction rates. • DNA barcoding could provide the answers.

  17. Conclusion Isn’t DNA Barcoding great?

  18. Recorded debate on DNA Barcoding at: www.conferences.uiuc.edu/peet/video.html

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