Judul: Marka SNAP Berbasis Fragmen Gen SAD sebagai Indikator Kandungan Asam Lemak Tidak Jenuh Kelapa Sawit
Abstrak: Kelapa sawit merupakan salah satu tanaman penghasil minyak nabati utama dengan produktifitas per hektar tertinggi dibandingkan semua tanaman penghasil minyak lainnya. Kebutuhan terhadap kualitas minyak nabati yang sehat dengan harga yang murah menjadi tren pada perkembangan industri minyak dan asam lemak secara global, diharapkan kelapa sawit dapat memenuhi kebutuhan tersebut. Oleh karena itu perlu dikembangkan materi genetik dengan produktifitas yang tinggi dan kualitas minyak yang baik, sebagai sumber bahan pangan maupun non pangan. Salah satu cara mempercepat mendapatkan tanaman unggul yang memenuhi kriteria yang diinginkan adalah dengan mengembangkan marka molekuler yang dapat mengindikasikan kualitas minyak yang dihasilkan tanaman kelapa sawit sejak dini. SNPs (Single Nucleotide Polimorphisms) merupakan salah satu teknologi marka molekuler, selain pemuliaan konvensional yang dapat dimanfaatkan untuk memperkuat dan mempercepat program pemuliaan kelapa sawit. Kualitas minyak dipengaruhi oleh kandungan asam lemak tidak jenuh pada minyak. Asam oleat merupakan salah satu komponen utama asam lemak tidak jenuh tunggal yang baik untuk kesehatan, bersifat stabil dan mampu mengurangi resiko serangan penyakit jantung. Pembentukan dan kandungan asam oleat serta asam lemak tidak jenuh pada kelapa sawit dipengaruhi oleh gen kunci stearoyl ACP desaturase (SAD). Gen ini memainkan peran penting dalam menentukan komposisi asam lemak tidak jenuh pada kelapa sawit (Elaeis sp.). Dalam penelitian ini, fragmen gen SAD diisolasi dari genom sumber keragaman kelapa sawit untuk mengidentifikasi dan meanganalisis lokus SNP yang digunakan sebagai dasar pengembangan marka SNAP (Single Nucleotide Amplified Polimorphisme). Dua pasang primer gen SAD spesifik berhasil didisain untuk mengisolasi fragmen gen SAD dari genom sumber keragaman kelapa sawit, yakni primer SAD1 dan SAD2. Fragmen gen SAD telah berhasil diisolasi dan diamplifikasi dari DNA genom 5 aksesi kelapa sawit yang terdiri atas satu aksesi spesies E.oleifera (open polinated) dan 4 aksesi dari spesies E.guineensis var tenera, Dura, Pisifera, dan Virescens. Fragmen gen SAD yang diisolasi dari berbagai sumber keragaman kelapa sawit mempunyai tingkat homologi 99% dengan gen SAD yang terdeposit di NCBI (National Center for Biotechnology Information). Primer SAD1 berhasil mengamplifikasi semua sampel dengan ukuran 1100 bp dengan satu intron ukuran 507 bp. Primer SAD2 menghasilkan urutan basa dengan ukuran 600 bp. Total ukuran exon yang teramplifikasi berkisar antara 969-1032 bp. Hasil identifikasi dan analisis sekuens SAD menghasilkan 13 lokus SNPs gen SAD, yang kemudian dikembangkan untuk mendapatkan 26 pasang marka SNAP. Diantara 13 lokus SNP yang dievaluasi, terdapat enam (6) lokus marka SNAP (2 lokus di bagian intron, 3 lokus di bagian exon, dan 1 lokus di bagian 3’UTRs), yang dapat digunakan untuk menduga variasi aktivitas biosintesis dan komposisi asam lemak tidak jenuh dalam buah kelapa sawit umumnya dan kandungan asam oleat pada khususnya. Ini adalah hasil penelitian pertama yang menunjukkan gabungan lokus SNPs pada exon, intron dan 3’UTRs dapat mengindikasikan kandungan asam lemak tidak jenuh pada tanaman penghasil minyak nabati. Hasil penelitian ini dapat dimanfaatkan oleh industri benih kelapa sawit untuk mendapatkan induk superior dengan kandungan asam oleat yang tinggi, meningkatkan efisiensi seleksi dan mengurangi jumlah generasi silang balik pada backcross E.oleifera dan E.guineesis, mengindentifikasi tanaman tenera yang mengalami mutasi alami pada gen SAD dengan komposisi kandungan asam lemak spesifik yang dapat diperbanyak dengan teknik kultur jaringan sehingga didapatkan tanaman
Keyword: Elaeis guineensis, E. oleifera, Asam oleat, SAD (Stearoyl ACP Desaturase), SNPs, SNAP

Judul: Development of Single Nucleotide Polymorphisms (SNPs) Marker based on SAD Gene in Oil Palm (Elaeis guineensis Jacq.)
Abstrak: Oil palm (Elaeis guineensis Jacq.) is an important economic crop species due to the versatile applications of its crude and kernel oils. The necessity to improve oil palm, which is the world’s most productive oil producing plant under cultivation currently for high yield and oil quality to meet the growing global demand especially in term of its healthy component, oleochemical industrial needs and biodiesel utilization has become a major area of focus for oil palm breeders. Marker assisted selection have played a crucial role in oil palm breeding programs and single nucleotide polymorphism (SNP) maker is one of those technology that has recently attracted breeders. High content of oleic acid (18:1) has proven to be that needed component of oil palm and other vegetable oils that can greatly contribute to oil quality improvement. Stearoyl Acyl-carrier-protein Desaturase (SAD) is a key enzyme for oleic acid biosynthesis which plays an important role in determining the composition of unsaturated fatty acids in oil palm. In oil palm, SAD gene is located in chromosome 7, 8, and 9. This research focused on chromosome 7 and 9. There are 3 exon region in each of these two chromosomes. Specific primers were designed base on the 6 exon and neighboring intron region. Genomic DNA from three oil palm sources were amplified using these specific primers. We identified 9 SNP loci (4 in the exon and 5 in the intron) in SAD gene fragment and developed 9 allele-specific single nucleotide amplified polymorphism (SNAP) marker for oleic acid prediction. Four out of the nine SNAP marker developed and tested on 25 oil palm accessions were polymorphic and reasonably informative. The average expected and observed heterozygosities were 0.391 and 0.404, respectively. The mean polymorphism information content (PIC) was 0.312. Our results showed that these SNAP markers will be useful if validated in larger oil palm population in predicting oleic acid composition and genetic variation in oil palm breeding programs based on SAD gene fragment. This research account for the first specific study of SNAP marker development based on SNPs loci in both intron and exon region of SAD gene sequence in chromosomes 7 and 9 of oil palm. The result of our research will allow direct MAS specifically for oleic acid content and generally for unsaturated fatty acid prediction in oil palm at an early growth stage with less resources and time and also carried on genetic diversity analysis based on SAD gene. In addition, this research result will have set the pitch for further genetic diversity studies on the progeny of cross between the species of oil palm (E.guineensis and E.oleifera). Initial evaluation of the SNAP markers developed in this study is significantly beneficiary for oil palm breeders.
Keyword: Allele-specific, expected heterozygosities, observed heterozygosities, oil quality, SAD, SNP

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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