Growing degree-day. Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the date that a flower will bloom, an insect will emerge from dormancy, or a crop will reach maturity.
Cystic fibrosis is a genetic condition caused by a faulty gene (known as the CFTR gene). The CFTR gene normally creates a protein that moves salt and water out of a cell.If the CFTR gene is defective, it results in a build-up of thick, sticky mucus in the body's tubes and passageways.ystic fibrosis is a genetic condition caused by a faulty gene (known as the CFTR gene). The CFTR gene normally creates a protein that moves salt and water out of a cell.
The CF gene was discovered in 1989 on chromosome pair 7 -- volume 7 in our genetic encyclopedia -- by researchers supported by the CF Foundation. Cystic fibrosis is an example of a recessive disease. That means a person must have a mutation in both copies of the CF gene to have CF.ystic fibrosis is caused by mutations in the gene that produces the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This protein is responsible for regulating the flow of salt and fluids in and out of the cells in different parts of the body.