Genetics is the study of genes, genetic variation, and heredity in living organisms. A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins.
The Human Genome Project has estimated that humans have 20,000 - 25,000 genes. Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but less than 1% of genes are slightly different between people. Poplar tree genome suggests more than 45,000 genes.
Grains are small, hard, dry seeds, with or without attached hulls or fruit layers, harvested for human or animal consumption. The two main types of commercial grain crops are cereals (e.g. wheat, rye) and legumes (e.g. beans, soybeans). Seeds
After being harvested, dry grains are more durable than other staple foods, such as starchy fruits (e.g. plantains, breadfruit) and tubers (e.g. sweet potatoes, cassava). This durability has made grains well suited to industrial agriculture, since they can be mechanically harvested, transported, stored for long periods, and milled for flour or pressed for oil. Major global commodity markets exist for canola, maize, rice, soybeans, wheat, and other grains but not for tubers, vegetables, or other crops.