Data Mining for Simple Sequence Repeats in Oil Palm Expressed Sequence Tags

Expressed Sequence Tags or ESTs are small pieces of DNA sequence that are generated by sequencing either one or both ends of an expressed gene. ESTs provide researchers with a quick and inexpensive route for discovering new genes, for obtaining data on gene expression and regulation, and for constructing genome maps. Oil palm EST sequences as available in public domain are downloaded. They were grouped and made contigs using CAP3 and Phrap. Microsatellite repeats are located using 5 softwares (MISA, TRA, TROLL, SSRIT, SSR primer). Among the 5 methods MISA is found to be the best. It can elucidate the compound repeat also. Frequency and total number (202) of SSR were detected. Mononucleotide repeat is more abundant especially ‘A/T’ repeats in Oil palm. Flanking primers were designed using primer3, SSR primers. The results of the study are given as an online database ‘MEMCO’ to help Oil palm researchers

Interspecific differences in single nucleotide polymorphisms (SNPs) and indels in expressed sequence tag libraries of oil palm _Elaeis guineensis_ and _E. oleifera_

Oil palm is the second largest source of edible oil, which meets one-fifth of global demands of oils and fats. Expressed sequence tag (EST) sequencing programs have provided a wealth of information, identifying novel genes from a broad range of organisms and providing an indication of gene expression level in particular tissues. It also provides the richest source of biologically useful SNPs due to the relatively high redundancy of gene sequence, the diversity of genotypes represented within databases. EST based SNPs are potential molecular markers and aid in genetic improvement. A total of 21062 and 2053 polymorphic (SNP and Indel) sites in _E. guineensis_ species and in _E. oleifera_, 4955 SNPs and 1172 Indels were detected. SNP(17.5/kbp) and Indel(4.1/kbp) frequency was higher in _E. oleifera_ than _E. guineensis_ species (16.8/kbp, 1.6/kbp). _E. oleifera_ showed higher transition to transversion ratio (1.40) than in _E. guineensis_ (1.02). The ratio of Ts vs Tv showed, the genetic divergence is occurring in this crops in different fashion and _E. guineensis_ had diverged more than _E. oleifera_. We provide the results of the study as online database ("http://riju.byethost31.com/oilpalm/":http://riju.byethost31.com/oilpalm/) for use by oil palm breeders

SSR - Identification from EST

Tutorial of Identification of SSR from EST resources using online Tool