From Scientific American:
Found in cuisines worldwide, chilies and peppers—name them as you wish—all belong to the Capsicum genus, which is native to America. And recent genetic studies confirm that they have a single common ancestor that emerged about 16.8 million years ago.
“Their origin is recent within the Solanaceae family, to which potatoes and tomatoes also belong,” says Mauro Grabiele, author of several genetic and chromosomal studies of 22 Capsicum species in preparation for his doctoral thesis. Now Grabiele is a researcher at the Institute of Subtropical Biology of the National Scientific and Technical Research Council (CONICET) in Buenos Aires and the National University of Misiones.
His research also found three distinct groups that were established early during the Capsicum lineage’s evolution: Andean chilies with 26 chromosomes; another group from the coast of Brazil, also with 26 chromosomes; as well as 24-chromosome Andean chilies.
There are five species grown commercially: three subspecies of the complex Capsicum annuum (C. annuum, C. frutescens and C. chinense), along with C. baccatum and C. pubescens. All of them have a common origin and belong to the lineage of 24-chromosome Andean chilies. Of these, the best known commercial varieties are cayenne, jalapeño, tabasco and sweet peppers of the species C. annuum; rocoto and manzano peppers of C. pubescens; habaneros, panca and limo of C. chinense; and cristal, escabeche and green of C. baccatum, to name a few.
Grabiele explains that the wild species have the genetic potential to be crossed with the cultivated ones and gain some economically important qualities such as organoleptic properties (taste, color, spiciness) and resistance to drought and disease. “Particularly, wild C. chacoense and cultivated and wild species of the C. annuum and C. baccatum complex are able to interbreed giving fertile offspring,” Grabiele explains.
The same applies to C. pubescens and its wild C. eximium …