who discovered it?
Gregor Mendel
Gene
The existence of discrete inheritable units was first suggested by Gregor Mendel (1822–1884).
where are genes found in a cell and what are they composed of It is a sequence of nucleotides in DNA or RNA.
wiki:15827885
Gene [SEP] Discovery of discrete inherited units
The existence of discrete inheritable units was first suggested by Gregor Mendel (1822–1884). From 1857 to 1864, in Brno, Austrian Empire (today's Czech Republic), he studied inheritance patterns in 8000 common edible pea plants, tracking distinct traits from parent to offspring. He described these mathematically as 2 combinations where n is the number of differing characteristics in the original peas. Although he did not use the term "gene", he explained his results in terms of discrete inherited units that give rise to observable physical characteristics. This description prefigured Wilhelm Johannsen's distinction between genotype (the genetic material of an organism) and phenotype (the observable traits of that organism).