j, IMIKKII W I IN i.l'INEA-PIGS. 



,1 ,, being undent 1 thai the red eye is invariably associated with 



low in the ooat, 



I ,ur of the five [ca mothers which were mated with ^54 had pro- 



duced silver agouti red-eyed) young by lea mates. Each of them 



pril .j,. l-eyed young by o*54; 1 1 >ge1 her they produced 5 dark-eyed 



■ . .l.l.-n agouti) and 6 red-eyed (silver agouti or sepia). The 



fifth fca mother 509) had produced 11 golden agouti young when 



mated with [ca males known to be heterozygous for silver agouti. 



a ble 12. This is good evidence that she did not carry red-eye as 



., character and was accordingly homozygous for dark-eye. 



By '64 she produced 2 golden agouti young. 



From these several tacts it appears that dark-eyed lea animals 

 capable of producing red-eyedyoung when mated inter se, produce equal 

 Qumbers of dark-eyed and red-eyed young when mated to albinos, but 

 produce qo albinos. This indicates that albinism is recessive both to 

 red-eye and dark-eye, an indication which the F 2 result confirms. It 

 will be shown further that the three conditions are mutually allelomor- 

 phic, bo thai a sygote may contain any two of the three, but not more. 



d-eye is in fad a fourth member of the albino series of allelomorphs, 

 which include- the following conditions in order of dominance: (1) ordi- 

 nary dark-eye and colored coat, such as is seen in Cavia cutleri and in 

 golden agouti animals of the lea race; (2) dark-eye with dilute coat, 



d in colored animals of race C; (3) red-eye and non-yellow coat; 

 l albino. (See Wright, 1915.) For convenience these allelomorphs 

 may be designated by C, C<], C r , and C a . The cross of lea females 

 with the albino o*54 involves animals of the formulae CC or CC r mated 

 with an animal of the formula C a C a . The 7 golden agouti young are 

 expected to be of the formula CC a ; the 6 red-eyed young of the 

 formula I I We may now compare the experimental with the 

 expected results of breeding such animals in various ways. 



THE F, GENERATION. 



of the Fj silver agouti males (cf 517) was known from his pedi- 

 • be heterozygous in four characters, viz, red-eye vs. albinism, 

 non-agouti, black vs. brown, and extension vs. restriction. 

 Hie formula was accordingly C r C a AaBbEe, and we should expect him 

 form gametes of 16 different sorts, all equally numerous. This 

 animal was mated with all three kinds of F! females, with the results 

 shown in tabic 15. The golden agouti females produced 25 young, 

 distributed among 10 classes very distinctly different in appearance. 

 -outi females were known from pedigree to be hetero- 

 for the Bame 4 factors as c?517, but to contain a different allelo- 

 morph for albinism. Both he and they carried albinism as a recessive 

 • but whereas he carried red-eye (C r ) as its dominant allelo- 

 rph, they carried dark-eye it he ordinary condition of the color 



