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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.
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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
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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
Bribie Island
Midway
Kauai
Perth
Taranaki
Mt Maunganui
Riversdale
New Brighton
Brisbane Foxton
West Auckland
East Auckland
Abel Tasman Nelson
Hokitika
Himatangi Beach
AT2
F5
T4
R20
R3
NB4
HB2
HB5NB22
AW 2
F3
H53WA2
H2
T2
HB3
B6 B7
WA1
H2 NB10
R18
MM2
MM1
MM4
R4 MM3
AW 15
NB32
AE 10 WA6 H4 NB3 NB7 N2
T3 T1
NB2 NB9 NB10 WA3
N1 NB7
R13
H3
WA2 AW 2 R2 HB1 F1
B10
F2
H1
NB8
NB109
R18
MM2
MM1
MM4
R4
MM3
R13
R1
NB103 N1
B7 WA1
Bribie Is 1
Physalia physalis
AT2
F5
R20
NB4 F2
HB3
H1
NB10NB8
AE10 WA6 H4 NB3 NB7
F5 H3
T4 R3
NB32NB22
H53
T2
H2
NB2 NB9 WA3 WA2 AW2 NB5 R2 F3 HB1 F1
AE15
AE14T3
HB2 HB5
Kauai 1 Bribie Is 2Bribie Is 3
N2
Midway 1
NB109
Kauai 2
B10
B9
N3
1 change
Likelihood trees
COI ITS
Physalia physalis
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?
AT2
F5
T4
R20
R3
NB4
HB2
HB5NB22
AW 2
F3
H53WA2
H2
T2
HB3
B6 B7
WA1
H2 NB10
R18
MM2
MM1
MM4
R4 MM3
AW 15
NB32
AE 10 WA6 H4 NB3 NB7 N2
T3 T1
NB2 NB9 NB10 WA3
N1 NB7
R13
H3
WA2 AW 2 R2 HB1 F1
B10
F2
H1
NB8
NB109
Conflict
A B
Tree 1
DC
A
B D
C
Tree 2
60% 40%
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
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