HEREDITY IN PLANTS, ANIMALS, AND MAN. BOT 
The seeds from this generation were collected and separately sown. 
The plants from the green seeds, when self-fertilised, produced all green 
seeds, and when these were again sown plants producing all green seeds 
again resulted. The pure recessive green variety had, therefore, com- 
era @ x O 
PARENT GENERATION.” 
FIRST FILIAL CENERATION. FI 
pa ee 
, O ceneratY F2 
4 ‘é< / i | 
@® @e6e@ 0 @ a @0 O cENERATN FS 
] | 
PURE PURE \/ ee PURE PURE YY PURE PURE 
CIVES HYBRID HYBRID CIVES 
ONLY YELLOW ONLY CREEN 
DESCENDANTS DESCENDANTS. 
YELLOW AND GREEN PEAS. 
ye.cow 1s DOMENANT. — creenis RECESSIVE. 
FIF2,F3, plants WERE ALL SELF-FERTILISED. 
DIAGRAM I. 
pletely segregated, or separated out from the hybrid, and the pure strain 
was completely recovered. 
The yellow seeds, on the other hand, behaved differently. Two kinds 
of plants were produced, one kind which on self-fertilisation gave all 
yellow seeds, the other kind which gave both green and yellow, the two 
colours being in the proportion of three yellow to one green. There were 
twice as many plants which gave both green and yellow seeds as there 
were plants which gave only vellow. Peas from the kind which produced 
only yellow peas, when sown, produced plants which again gave all 
yellows, and this continued in succeeding generations. The pure dom- 
inant yellow variety, like the green recessive, had completely separated 
out and was re-established. 
What happens will be clear from the diagram. 
The fact that one of a pair of characters is domimant and the other 
recessive is not, however, a primary or essential feature of the scheme of 
Mendelian inheritance. When one character is dominant the hybrid has 
the appearance of the parent which bore that character, but in other cases 
the hybrid appears quite different from either parent. This is well illus- 
trated by the case of the Andalusian Fowl figured in Diagram 2. The 
Blue Andalusian is a variety well known to the poultry fancier. It was 
known that the strain was not pure, and that when bred together the birds 
gave not only blues, but also some blacks and some splashed whites —a 
white with splashes of dark colour on the feathers. After the rediscovery 
of Mendel’s work this case was investigated by Bateson and Punnett, 
