Genetics and Molecular Research 16 (2): gmr16029647 Development of TRAP primers for Ricinus communis L. K.S. Simões, S.A. Silva, E.L. Machado and H.S. Brasileiro Núcleo de Melhoramento Genético e Biotecnologia, Centro de Ciências Agrárias Ambientais e Biológicas, Universidade Federal do Recôncavo da Bahia, Cruz das Almas, BA, Brasil Corresponding author: K.S. Simões E-mail: karinesimoes01@hotmail.com Genet. Mol. Res. 16 (2): gmr16029647 Received February 16, 2017 Accepted March 16, 2017 Published April 13, 2017 DOI http://dx.doi.org/10.4238/gmr16029647 Copyright © 2017 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution ShareAlike (CC BY-SA) 4.0 License. ABSTRACT. The objective of this article was to develop TRAP (target region amplifcation polymorphism) primers for castor bean, with the goal of making functional markers available for genetic studies about the species. To do this, oligonucleotides were designed based on ESTs, obtained from the NCBI (National Center for Biotechnology Information) databank, which code enzymes involved in metabolic routes of fatty acid synthesis, ricin synthesis, and resistance to castor bean pathogens. The forward primers were designed with the help of the Primer3 software and, for the reverse, six arbitrary primers were used. To standardize the amplifcation reactions, the following criteria were used to select the primers: sizes between 18 and 20 bp, guanine/ cytosine (GC) in the range of 40 to 60%, and average annealing temperature between 55° and 62°C. The design quality of the primers was verifed using the Net Primer application. Fifty-six primers were designed, which had an average GC percentage of 53.2%. A total of 336 combinations were obtained using the 56 fxed and 6 arbitrary primers. Based on polymerase chain reaction, 330 combinations (89%) presented good amplifcation patterns for the genomic DNA of castor