Finding relationships and differences
by bar-coding jellyfish species
Dr. David Pontin
A beginning
Barcodes
• Barcode: A short series of vertical bars
representing the digits 0-9, commonly used
for product identification.
• DNA Barcode: A short length of DNA that is
able to differentiate between species.
caggggcacgaatcagttaccaaatcctccaattagaact
ggcattacaaggaaaaagatcataacaaatgcatgagca
gttactataacattatagagatgatcatctccaaacatggt
accaggtcctgacaa
Looking for DNA Barcodes
•
•
•
•
Mitochondrial DNA vs. Nuclear DNA
“fast evolving” tips only of interest
Must work in >90% of examples
650 bp length of Mitochondrial DNA called
cytochrome c oxidase I or COI
DNA Barcoding today
• Formally Described Species :72,144
• Total Barcode Records 871,435
• Barcode of life project
caggggcacgaatcagttaccaaatcctccaattagaact
ggcattacaaggaaaaagatcataacaaatgcatgagca
gttactataacattatagagatgatcatctccaaacatggt
accaggtcctgacaa
A bit of controversy
• What constitutes a species?
– Rule of thumb for insects is 2% divergence (13bp)
• Cryptic species/species complexes
– DNA vs. morphology
• COI doesn't work for everything (plants)
– Is one gene enough?
Physalia (Siphonophora)
• Completely pelagic
• Taxonomically
ambiguous
• Abundant around
New Zealand
• Passive surface
dispersal
PhD. goals
1. Identify the species
2. Identify important oceanographic variables
that influence bluebottle occurrence
3. Predict bluebottle occurrence
Portuguese Man o War
Physalia physalis
The Bluebottle
Physalia utriculus
Bluebottle locations
• 54 specimens
• 13 locations
• COI and ITS
sequenced
Midway
Kauai
East Auckland
West Auckland
Mt Maunganui
Taranaki
Bribie Island
Brisbane
Perth
Himatangi Beach
Abel Tasman
Nelson
Hokitika
Riversdale
Foxton
New Brighton
Likelihood trees
R18
COI
ITS
MM2
MM1
R13
MM1
MM3
R18
MM2
R4 MM3
MM4
R13
R1
MM4
R4
WA1
H2 R20 AE15
HB3
AE10 WA6
NB10
H4 NB3
F5 NB8
NB7
H1
T4 R3
N3
B7
B9 WA1
Midway 1
Kauai 2
Kauai 1
B10
NB109
N2
B10
B6 B7
AE14
T3
F2 AT2
NB4
H53
NB32
NB22 T2 NB2 NB9 WA3
F5 H3 WA2 AW2
HB2 HB5 NB5 R2 F3
HB1 F1
Bribie Is 1
Bribie Is 2
Bribie Is 3
NB103
N1
NB2
NB4 NB9
F5
NB10
WA3
AT2
HB2
AW 2 HB3
F3
NB109
F2
Physalia physalis
1 change
R3
R20
HB5 H53
NB22
H1
N1 NB7
H2 NB10 AE 10 WA6 H4
NB3 NB7 N2
T2
AW 15 WA2 AW 2
R2 HB1 F1
H3
NB8
Physalia physalis
NB32
T3 T1
H2
WA2
T4
Genetic linkages (COI)
Hybridisation?
• Two explanations for the ones that
“jumped ship”
– Hybridisation
– Ancestral polymorphisum
• More likely to be hybridisation
– Range overlap
– Broad cast spawning
– Reported in the Anthozoa
Western Australia 1
• Doesn't fit any clan
• If removed, green
clan is well supported
• What’s going on?
R18
MM1
MM2
R4 MM3
R13
MM4
WA1
B10
B6 B7
NB2
NB4 NB9
F5
NB10
WA3
AT2
HB2
AW 2 HB3
F3
NB109
F2
R3
HB5 H53
NB22
H1
N1 NB7
H2 NB10 AE 10 WA6 H4
NB3 NB7 N2
T2
AW 15 WA2 AW 2
R2 HB1 F1
H3
NB8
R20
NB32
T3 T1
H2
WA2
T4
Conflict
Tree 2
Tree 1
A
C
B
A
60%
40%
D
B
C
D
Achieving goals (or not)
• We still don’t know what species of
bluebottle occurs in New Zealand
• But it is a species complex needing a
global review
• COI was a good choice but results
heighted the need for other markers with
“difficult” species
Hypothesised
movement of
Physalia
Hypothesised
blooming zone
Synergy
Both techniques confirm the existence of
two circulatory systems
 Molecular data shows what’s there and the
models suggest how it got there
 Methods allow potential blooming areas to
be inferred so that other evidence can be
examined in a directed manner
 Not possible if methods are considered
independently

Wider Picture
• How many other jellyfish species could be
the same? What does that mean for New
Zealand's marine biodiversity?
• Population identification has several usages
– Pest control: resistance
– Population linkages