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