Indonesia is the center of marine biodiversity

Comparison of dispersal in two sea stars, Linckia

laevigata and Protoreaster nodosus, across a known

geographic barrier.

Martha Muñoz, Bola Akinronbi, and Paul Barber (BUMP)

Indonesia is the center of marine biodiversityIndonesia is the center of marine biodiversity

Fish

Corals

Snails

Coastal marginsduring glacial maxima

Pleistocene Sea Level Fluctuations

After Voris 2002 400km

Lavery et al. 1996

McMillan & Palumbi 1996Williams & Benzie, Benzie & Williams 1997

Duke et al. 1999

Linkia laevigata

Williams et al. (2000).

GOALS

To examine the genetic structure of Linckia laevigata

across a broad geographic scale and refine the location of a

biogeographic break.

To determine the degree of similarity genetic structure

between Linckia laevigata and Protoreaster nodosus, which have

similar larval pelagic dispersals.

Protoreaster nodosus

F-statisticsF-statistics

Fst: measure of genetic divergence by examining allelic

content.

Ranges from 0-1.

“0” means there is no genetic difference between sub- and

total population.

“1” means the sub- and total population are not related at all.

It is used to infer gene flow.

MethodsI. Sampling

JavaSulawesi

Halmahera

Papua

I. Sampling in the field- Collected 377 Linckia and 115

Protoreaster from 23 localities.

II. DNA extractions were performed using a 10% Chelex solution and

samples were incubated overnight.

III. Amplifications of mitochondrial CO-1 were performed and

fragments varying from 658 to 890 base pairs were isolated.

MethodsMethods

IV. Isolated CO-1 fragments were sequenced on an ABI 377 using

ddNTP terminator chemistry

V.Resulting fragments were proofread using Sequencher software and

fragment alignments were visually made.

VI. Minimum-spanning trees and F-statistics were determined using

Arlequin software.

MethodsMethods

Linckia laevigata Minimum Spanning

Tree

Gray Clade

White Clade

Black Clade

Clades were separated by 8 mutational steps.

ResultsResults

Linckia laevigata

Relative Clade

Distribution

White

Clade

Gray Clade

Black Clade

Protoreaster Haplotype Network

Protoreaster

Linckia

Protoreaster

WestWest

EastEast

---------------------------------------------------------------------- Source of Sum of Variance Percentage variation d.f. squares components of variation----------------------------------------------------------------------Between East and West 1 35.001 0.13108 Va 2.93

Within East orWest Groups 21 181.828 0.26882 Vb 6.02

Within populations 373 1517.555 4.06851 Vc 91.05---------------------------------------------------------------------- Total 395 1734.384 4.46841---------------------------------------------------------------------- Fixation Indices FSC : 0.06198, p=0.0000 FST : 0.08949, p=0.0000 FCT : 0.02933, p=0.0127----------------------------------------------------------------------

Fst and Genetic Variance Between Indian and Pacific Ocean Populations of Linckia

Fst and Genetic Variance Between Indian and Pacific Ocean

Populations of Protoreaster---------------------------------------------------------------------- Source of Sum of Variance Percentage variation d.f. squares components of variation----------------------------------------------------------------------Between EastAnd West 1 1.787 0.01279 Va 1.58

Among populationswithin Eastor West 9 10.259 0.03303 Vb 4.08

Within populations 121 92.370 0.76339 Vc 94.34---------------------------------------------------------------------- Total 131 104.417 0.80921---------------------------------------------------------------------- Fixation Indices FSC : 0.04147, p=0.0088 FST : 0.05662, p=0.0098 FCT : 0.01581, p=0.1642----------------------------------------------------------------------

y = 0.4229x + 0.0096

R2 = 0.6225

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.05 0.1 0.15 0.2 0.25 0.3

Linckia

Protoreaster

Fst of Linkia vs. ProtoreasterFst of Linkia vs. Protoreaster

ConclusionsConclusions

High diversity in haplotypes with some High diversity in haplotypes with some

regional differentiation of clades.regional differentiation of clades.

LinckiaLinckia

ProtoreasterProtoreaster

ProtoreasterProtoreaster LinckiaLinckia

ConclusionsConclusions

Three major clades among Three major clades among Linckia Linckia andand

Protoreaster. Protoreaster. Star phylogenies suggest recentStar phylogenies suggest recent

range expansions.range expansions.

ConclusionsConclusions

Variation across a geographic gradient is positively orrelated between Variation across a geographic gradient is positively orrelated between

Protoreaster Protoreaster and and Linckia. Linckia. These similar taxa disperse and exchange These similar taxa disperse and exchange

genes in similar patterns.genes in similar patterns.y = 0.4229x + 0.0096

R2 = 0.6225

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.05 0.1 0.15 0.2 0.25 0.3

Linckia

Protoreaster

Broader ImplicationsBroader Implications

Similar taxa, such as Similar taxa, such as Linckia Linckia and and ProtoreasterProtoreaster

can display similar patterns of dispersal.can display similar patterns of dispersal.

Marine protected areas require ranges largeMarine protected areas require ranges large

enough to ensure adequate gene flow.enough to ensure adequate gene flow.

Acknowledgments

Thank you to Paul Barber, Bolanle Akinronbi, Elizabeth Jones,

and Eric Crandall for support both in the laboratory and in the

field.

NSF for funding