Transformants

In genetics, a transformant is a cell or organism that has acquired new genetic material through the process of transformation. Transformation refers to the uptake and expression of exogenous DNA from the surrounding environment, or its integration into the genome.

In bacteria, competent cells can take up DNA from lysed cells or purified plasmids. The introduced DNA may replicate as a plasmid or integrate into the chromosome, giving the transformant new traits such as antibiotic resistance or metabolic capabilities.

Laboratory methods to generate transformants include chemical transformation with calcium chloride and heat shock, and electrical poration (electroporation). In plants and some animals, transformation is achieved through methods such as Agrobacterium tumefaciens–mediated transfer, lipofection, or viral vectors.

Transformants are identified by selective growth on media containing antibiotics or other markers, and their DNA can be confirmed by PCR, sequencing, or reporter assays. The concept originated from Griffith's transformation experiments and was later clarified as DNA-based heredity, establishing a foundation for modern cloning, genetic engineering, and biotechnology.