KEANEKARAGAMAN GENETIK IKAN BIAWAN (Helostoma temminckii Cuvier, 1829) DARI PROVINSI RIAU BERDASARKAN GEN MITOKONDRIA COI DAN KARAKTER MORFOLOGIS

Aldy Riau Wansyah Hasibuan, Prof. Dra. Tuty Arisuryanti, M.Sc., Ph.D.

2025 | Tesis | S2 Biologi

Ikan biawan (Helostoma temminckii) merupakan ikan air tawar ekonomis yang banyak ditemukan di ekosistem rawa gambut di Provinsi Riau. Penelitian ini bertujuan menganalisis keanekaragaman genetik ikan biawan melalui pendekatan morfologis dan molekuler berdasarkan gen mitokondria Cytochrome Oxidase Subunit I (COI). Sebanyak 30 sampel dikoleksi dari Kampar, Siak, dan Pelalawan. Analisis morfometrik dan meristik menggunakan SPSS V.26 melalui Principal Component Analysis menghasilkan 2 fungsi dengan nilai eigen 163,127 yang menjelaskan 79,7% variasi morfologis. Karakter dominan pembeda populasi adalah panjang kepala, tinggi badan, dan panjang awal sirip dorsal hingga akhir sirip anal. Scatter plot menunjukkan pemisahan individu antar populasi yang mencerminkan adaptasi terhadap kondisi rawa gambut. Analisis molekuler menghasilkan fragmen sepanjang 549 bp dengan similaritas 98,91–99,27% terhadap H. temminckii di GenBank. Model evolusi terbaik ditentukan menggunakan jModelTest, dan model HKY + G dipilih berdasarkan Akaike Information Criterion (AIC) untuk analisis Bayesian Inference (BI). Pohon filogenetik Neighbor Joining, Maximum Likelihood, dan BI menunjukkan nilai dukungan 100/100/1 dengan satu klaster monofiletik. Jarak genetik 0,00–0,92% menunjukkan variasi rendah dalam kisaran intraspesifik. Komposisi nukleotida didominasi basa A+T (54,5–54,9%), dengan haplotype diversity 0,533–0,676 dan nucleotide diversity 0,00130–0,00206. Nilai Tajima’s mendekati (?0) pada Kampar dan Pelalawan mengindikasikan ekspansi populasi, sedangkan nilai positif di Siak menunjukkan netralitas. Delapan haplotipe dibedakan oleh lima situs polimorfik dengan dominasi mutasi transisi synonymous. Analisis AMOVA menunjukkan 20% variasi antar populasi dan 80?lam populasi dengan nilai Fst –0,01852–0,27951. Hasil ini menegaskan bahwa populasi H. temminckii di Riau masih satu spesies dengan variasi genetik adaptif terhadap lingkungan rawa gambut.

Kissing gourami (Helostoma temminckii) is an economically important freshwater fish commonly found in the peat swamp ecosystems of Riau Province. This study aimed to analyze the genetic diversity of H. temminckii using morphological and molecular approaches based on the mitochondrial Cytochrome Oxidase Subunit I (COI) gene. A total of 30 samples were collected from Kampar, Siak, and Pelalawan. Morphometric and meristic data were analyzed using SPSS v.26 through Principal Component Analysis (PCA), which produced two functions with eigenvalues of 163.127, explaining 79.7% of total morphological variation. The dominant traits distinguishing populations were head length, body depth, and the distance from the origin of the dorsal fin to the end of the anal fin. The PCA scatter plot showed separation among individuals from different populations, indicating morphological adaptation to peat swamp conditions. Molecular analysis yielded a 549 bp COI fragment with 98.91–99.27% similarity to H. temminckii sequences in GenBank. The best evolutionary model determined using jModelTest was HKY + G based on the Akaike Information Criterion (AIC) for Bayesian Inference (BI). Phylogenetic trees generated by Neighbor Joining, Maximum Likelihood, and BI showed strong support values (100/100/1) with a single monophyletic cluster. Genetic distances ranged from 0.00% to 0.92%, indicating low intraspecific variation. Nucleotide composition was dominated by A+T bases (54.5–54.9%), with haplotype diversity of 0.533–0.676 and nucleotide diversity of 0.00130–0.00206. Tajima’s values (?0) in Kampar and Pelalawan indicated population expansion, while a positive value in Siak suggested neutrality. Eight haplotypes were distinguished by five polymorphic sites dominated by synonymous transition mutations. AMOVA revealed 20% variation among populations and 80% within populations, with Fst values ranging from –0.01852 to 0.27951. These results confirm that H. temminckii populations in Riau belong to a single species with adaptive genetic variation to peat swamp environments.

Kata Kunci : DNA barcoding, Gen COI, Ikan biawan, keanekaragaman genetik, PCA.