Sequencing the peanut genome

Following the presentation from USAID, Dr. Peggy Ozias-Akins spoke with tour attendees about genomics. According to Ozias-Akins, genomics is the study of the structure and function of the total complement (DNA) of an organism. The genome sequence of the peanut plant’s progenitors is facilitating rapid discovery of molecular differences between cultivated peanut varieties. These differences are being tested for linkage to traits of importance to growers and industry. Discovering linkages will enable application of molecular tools to breeding in order to more rapidly combine traits of interest. As many folks know, the peanut-genome was released earlier this year. According to Ozias-Akins, the peanut is complicated genetically. This is due primarily to the fact it is a polyploid.

During her presentation, Dr. Ozias-Akins described DNA and how it works. DNA is strand of As, Ts, Cs and Gs. Each letter stands for a specific molecule or nucleotide that form strands. Each strand is a chromosome. The peanut has 40 chromosomes – 20 from each ancestor. There are over 2 billion molecules in the peanut genome. The process of understanding the genome sequence is extremely tedious and time-consuming. Technologies for sequencing has advanced over the last several years, and because of this, the cost to sequence is much less and more feasible to sequence crop genomes such as peanuts.

Dr. Ozias-Akins then went on to discuss molecular markers. She described what markers were and how they are important. The use of molecular markers as a substitute for phenotypic selection, aka marker-assisted breeding, requires that marker-phenotype associations be identified. These markers are potentially most useful for recessive traits, stacking genes for traits, quantitative traits and difficult phenotypes. The genome project is not just about generating sequence, but applying it in breeding.