Philippine Journal of Science
151 (S1): 255-260, Marine Botany
ISSN 0031 – 7683
Date Received: 04 Oct 2021

Phylogenetic Study of Sargassum polycystum
(Sargassaceae, Ochrophyta) in Eastern Samar,
Philippines Based on the Nuclear rDNA Sequences

Richard V. Dumilag1, Leni G. Yap-Dejeto2,3*, Melodina Fabillo4,
and Marilou Sison-Mangus3

1Fisheries Department, Sorsogon State University–Magallanes Campus,
Aguada Norte, Magallanes, Sorsogon 4705 Philippines
2Division of Natural Sciences and Mathematics,
University of the Philippines Visayas Tacloban College, Tacloban City 6500 Philippines
3Ocean Sciences Department, Institute of Marine Science,
University of California Santa Cruz, CA 95064 USA
4Queensland Herbarium, Department of Environment and Science,
Brisbane Botanic Gardens, Mt. Coot-tha Road, Toowong, Queensland 4066 Australia

*Corresponding author: lgyapdejeto@up.edu.ph

 

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Dumilag R et al. 2022. Phylogenetic Study of Sargassum polycystum (Sargassaceae, Ochrophyta) in Eastern
Samar, Philippines Based on the Nuclear rDNA Sequences. Philipp J Sci 151(S1): 255–260. https://doi.org/10.56899/151.S1.17

 

ABSTRACT

Sargassum polycystum is an economically important seaweed endemic to Southeast Asian waters. Genetic diversity studies conducted for this alga have been based on samples from various areas in the Indo-Pacific region. Here, we examined the phylogenetic patterns of S. polycystum in Eastern Samar, Philippines using the nuclear ribosomal DNA (rDNA) region – including ITS1, 5.8S gene, and ITS2. The phylogenetic and haplotype analyses using these loci indicate that the Eastern Samar samples contain 13 haplotypes. Using the ITS2 region sequences alone (to include other Indo-Pacific samples), we found that the number of Eastern Samar haplotypes was reduced to six, with one common haplotype found in Singapore and Indonesia. Our findings indicate that the genetic diversity of Eastern Samar S. polycystum is substantially higher than previously suggested. Consistent with the previous hypothesis, the populations of S. polycystum in Southeast Asian waters indicate a range expansion. The study could extend our understanding of the genetic diversities of S. polycystum in the Philippines and elsewhere.