No. 630] 



LIXKAGE IN BATS 



65 



mals of this sort could be used for further linkage work. 

 Even if none were found it seemed very probable that 

 from them albinos of this description could be produced. 



Accordingly all six albinos were mated to red-eyed yel- 

 low-hooded animals (rrSnSnaaCC) in order to determine 

 their compositions. The zygotic formulas of the six 

 proved to be as follows : 



lRRS.SUA, 



2RR8hShAa, 



IRRSSnaa, 



IRRSnSnaa, 



1RR* 



The one outstanding feature was that all six albinos were 

 homozygous for black-eyed (R), although without link- 

 age one should have expected that at least one would be 

 red-eyed (rr) and several heterozygous (Rr). This gave 

 a very strong indication of linkage and so further work 

 was pursued with this in view. 



To simplify matters we shall disregard all the genes 

 but R (and its allelomorph r) and C with its allelomorph 

 C a , and we shall also assume complete linkage. When the 

 above six albinos (RRCaCa), therefore, were crossed with 

 red-eyed yellows (rrCC) their black-eyed offspring would 

 be of the composition RC a rC. These black-eyed animals 

 when inbred, assuming complete linkage, would behave as 

 follows : 



RCa rCxRCu-rC = lRC a RCa (albino): 2RCa-rC (black- 

 eyed blacks) : 1 rCrC (red-eyed yellow). 



6 Black-eyed (B) animals may be distinguished from red-eyed (r) or al- 

 binos (C a ) at birth by the fact that their eyes already appear dark through 

 the skin, while red and albino eyes are as yet devoid of pigment. It is 

 only about two weeks after birth or just before the eyes open that the red 



albinos or pink^eyed^p) . One of the albino females being tested had 11 

 black-eyed (R) young which through some oversight were disposed of before 



