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

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 ltlt
Interspecific variation
5
DNA Barcoding
For example in moths and birds it has been shown
that
- Intraspecific sequence variation lt 0.5 .
- Interspecific sequence variation gt 5.
Recognised sister taxa generally show gt 3
sequence divergence.
Thus the general rule that gt 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
gt 3 Sequence Divergence
Unique food plants
Diverged 2 4 mya
Distinct Spp?
14
FABOV, HIHAMP INGCUP
lt 0.5 Sequence Divergence
Host plants not exclusive
Diverged lt 0.5 mya
???Distinct Spp???
15
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
Isnt DNA Barcoding great?
18
Recorded debate on DNA Barcoding at
www.conferences.uiuc.edu/peet/video.html