Table 1

Mendel's novel observations summarised. Mendel demonstrated that crossing parental plants bearing alternative forms (A) and (a) of any one of seven traits generated a F1 population of plants (not shown) all of which were hybrids (Aa). Each of these F1 hybrid plants displayed only one of the two alternative parental traits, defined as the dominating trait (A). When these F1 hybrid plants were allowed to self-fertilise, the ratio of dominant to recessive traits in the F2 population was always close to 3:1.

Pairs of parental plants
Their F2 progeny

Dominant traits (A)
Recessive traits (a)
Number of F2
plants examined
Dominant:recessive
trait ratio in the
F2 population

Green pods
Yellow pods
580
2.82:1
Axial flowers
Terminal flowers
858
3.14:1
Red flowers
White flowers
929
3.15:1
Long stems
Short stems
1064
2.84:1
Inflated pods
Constricted pods
1181
2.95:1
Round seeds
Wrinkled seeds
7324
2.96:1
Yellow seeds
Green seeds
8023
3.01:1

Porteous Theoretical Biology and Medical Modelling 2004 1:4   doi:10.1186/1742-4682-1-4