IDENTIFIKASI KERAGAMAN DAN HUBUNGAN GENETIK DELAPAN POPULASI ITIK LOKAL INDONESIA MENGGUNAKAN MARKER MIKROSATELIT

DWI NUR HAPPY H, Dyah Maharani, S.Pt., MP., Ph.D; Prof. Dr. Ir. Jafendi Hasoloan Purba Sidadolog, IPM.

2018 | Tesis | S2 Ilmu Peternakan

Sejumlah itik lokal telah ditetapkan sebagai rumpun itik lokal Indonesia hingga saat ini. Karakterisasi genetik menjadi penting dilaksanakan guna membantu penerapan strategi konservasi dan pemanfaatan sumber daya genetik ternak. Berdasarkan alasan ini, sebanyak 240 sampel genomik DNA dari 8 populasi itik: Alabio (AL), Mojosari (MJ), Magelang (MG), Rambon (RM), Pegagan (PG), Bayang (BY), Pitalah (BY) dan Turi (TR) dianalisis menggunakan 22 marker mikrosatelit. Penelitian dibagi menjadi 5 tahap: pengambilan sampel darah, isolasi DNA, amplifikasi marker mikrosatelit, penentuan genotip (genotyping), dan analisis data. Hasil menunjukkan adanya keragaman genetik yang relatif sedang antar populasi, dibuktikan dengan jumlah alel per lokus dari 3 (CAUD123, CAUD128, CAUD009) hingga 23 (CAUD048), dengan total alel pada semua lokus berjumlah 153 alel. Nilai observed (Ho) dan expected heterozigosity (He), dan polymorphism information content (PIC) pada semua lokus dan populasi (keragaman genetik antar populasi) berturut-turut yaitu 0.440, 0.566, dan 0.513. Defisiensi heterosigot pada keseluruhan populasi (F_IT = 0.237), disebabkan oleh adanya defisiensi heterosigot pada masing-masing populasi (F_IS = 0.114) dan perbedaan genetik yang sedang antar populasi (F_ST = 0.137). Keragaman genetik dalam setiap populasi juga dianalisis berdasarkan nilai jumlah alel per lokus, Ho, He, dan F_IS, dengan rata-rata nilai berturut-turut 4.313, 0.440, 0.485, dan 0.092. Keragaman genetik terendah dalam populasi terjadi pada Itik Alabio (He=0.368) dan tertinggi pada Itik Magelang (He=0.545). Analisis hubungan genetik antar populasi berdasarkan pasangan nilai F_ST, terdekat yaitu antara BY dan PG (0.051) dan terjauh antara MJ dan PT (0.367), sedangkan berdasarkan nilai Nei�s genetic distance, hubungan genetik terdekat yaitu terdekat antara RM dan TR (0.021) dan terjauh antara AL dan PT (0.155). Analisis filogenetik menggunakan metode neigbor-joining mengelompokkan populasi itik menjadi 2 klaster: klaster 1 (AL, MJ, MG) dan klaster 2 (BY, RM, PG, TR, PT). Analisis Bayesian menunjukkan populasi Itik Alabio, Mojosari dan Pitalah memiliki struktur genetik yang lebih seragam dibandingkan populasi yang lain. Secara keseluruhan, keragaman genetik yang relatif sedang pada populasi itik lokal Indonesia telah berhasil dideteksi menggunakan 22 marker mikrosatelit.

At least eight local duck breeds have been recognized and documented as national germplasm of Indonesia. It is necessary to genetically characterize the local duck breeds for aiding conservation and future improvement strategies. Thus, this study was carried out to asses the genetic diversity and phylogenetic of eight Indonesia local duck populations using microsatellite markers. In total, 240 individuals (30 individuals each population) from Alabio (AL), Bayang (BY), Magelang (MG), Mojosari (MJ), Pegagan (PG), Pitalah (PT), Rambon (RM) and Turi (TR) duck populations were genotyped using 22 microsatellite markers. The results showed moderate level of genetic diversity among populations, with a total of 153 alleles detected over all loci and populations, ranging from 3 to 22 alleles per locus. Observed (Ho) and expected heterozygosity (He), as well as polymorphism information content (PIC) over all loci and populations were 0.440, 0.566, and 0.513, respectively. Heterozygote deficiency in the overall populations (F_IT = 0.237), was partly due to the heterozygote deficiency within populations (F_IS = 0.114) and moderate level of genetic differentiation among populations (F_ST = 0.137). The number of alelles per locus, Ho, He, and F_IS were also used to asses the genetic diversity within each population, with mean value of 4.313, 0.440, 0.485, and 0.092, respectively. Alabio had the lowest genetic diversity (He=0.368) whereas the Magelang duck population had the highest genetic diversity (He=0.545). All duck populations studied except Alabio duck revealed to be inbreeding, depicted by the possitive mean value of F_IS, ranging from 0.037 to 0.171. The genetic distances were the shortest between RM and TR (0.021) and between BY and PG (0.051), while between AL and PT (0.155) and between MJ and PT (0.367) were the least genetically related, based on F_ST value and Nei�s genetic distances, respectively. The phylogenetic analysis showed that eight duck populations were grouped into 2 main clusters, resulting AL, MG, and MJ separated to the remaining populations. Further analysis of Bayesian clustering showed that some duck populations had genetically mixed together. We summarized that the present study revealed considerable genetic diversity of studied populations and thus, proper management strategies should be applied for preserving genetic diversity and preventing loss of alleles.

Kata Kunci : Keragaman genetik, Hubungan genetik, Marker mikrosatelit , Itik lokal Indonesia