Matthew Subia 1 , Paul Barber 2 1 CSU Monterey Bay, 2 Boston University
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Transcript of Matthew Subia 1 , Paul Barber 2 1 CSU Monterey Bay, 2 Boston University
Phylogeographic structure of Tridacna crocea across the
Indo West Pacific
“How diverse is your clam chowda?”
Matthew Subia1, Paul Barber2
1CSU Monterey Bay, 2Boston University
Giant Clam Importance
• Food
• Colorful decorations
• During 1960’s and 70’s annual landings estimated at 100-400 tons.
• In 1985, clams were included in the convention on International Trade in Endangered Species of Wild Fauna and flora
Concerns for Giant Clams
• Commercial and artisanal exploitation
• Bleaching
• Disease
• Pollution
• Poaching
Natural History of T. crocea
• Adults tend to burrow in coral in waters less than 10 m deep
• Hermaphroditic and reach sexual maturity in approximately 5-7 years
• Broadcast spawners– Sperm released first– Eggs follow
• Algal symbionts and filter feeders
Lavery et al. 1996
McMillan & Palumbi 1996Williams & Benzie, Benzie & Williams 1997
Duke et al. 1999
Objectives
• What are the patterns of genetic structuring of T. crocea in Indonesia?
• Is there evidence for limited genetic exchange among populations?
• Do they show Pacific-Indian Ocean split?
Methods
• Extracted DNA from T. crocea tissue samples using Chelex
• Amplified DNA using PCR and mtCO1 T. crocea specific primers
• Sequenced DNA using ABI 377
• Sequences aligned and edited using Sequencher 4.5
• Sequences analyzed in Arlequin 2.0
AMOVA Results
---------------------------------------------------------------------- Source of Sum of Variance Percentage variation d.f. squares components of variation ------------------------------------------------- --------------------- Among groups 5 955.468 3.70605 Va 39.60 Among populations within groups 12 233.243 0.97774 Vb 10.45 Within populations 269 1257.522 4.67480 Vc 49.95 ---------------------------------------------------------------------- Total 286 2446.233 9.35859 ---------------------------------------------------------------------- Fixation Indices FST : 0.50048 ---------------------------------------------------------------------- P(rand. value <= obs. value) = 0.00000+ - 0.00000
Pairwise Comparison
------------------------ Population pairwise FSTs ------------------------ Papua 1 Papua 2 E. Indo N. Indo S. Indo Aceh Papua 1 0.00000 Papua 2 0.54912 0.00000 E. Indo 0.28892 0.18212 0.00000 N. Indo 0.52310 0.03873 0.09190 0.00000 S. Indo 0.60368 0.03403 0.23377 0.05885 0.00000 Aceh 0.68351 0.67235 0.42528 0.56291 0.69159 0.00000
Conclusion
• T. crocea demonstrates a new pattern in comparison to previously studied species in this region
• Three distinct clades exist:– 1 in the far west– 1 in the far east– 1 in central
• Therefore, T. crocea shows regional genetic structure