The foundation of gene mapping in sexually reproducing species is the evaluation of recombination frequency among progeny. A recombinant type is a new genetic combination that was not present in the previous parent or grandparent individuals vs. a parental type that was present in the previous generation.
Brown body cockroaches with straight wings were mated to yellow body cockroaches with curved wings. The resulting progeny all had brown bodies and straight wings. However, when those resulting brown, straight-winged cockroaches were bred to yellow, curved-winged coach roaches, the resulting progeny numbers were observed:
|Brown, straight wings||63|
|Brown, curved wings||26|
|Yellow, straight wings||32|
|Yellow, curved wings||75|