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The Chemical Interpretation of some Mendelian Factors for 



Flower -Colour. 



By M. Wheldale, Fellow of Newnham College, Cambridge, and 

 H. Ll. Bassett, Trinity Hall, Cambridge. 



(Communicated by W. Bateson, F.R.S. Received November 21, 1913, — Read 



January 22, 1914.) 



(From the Laboratory of the John Innes Horticultural Institution, Merton, Surrey, and 

 the Balfour Laboratory, Cambridge.) 



The inheritance of flower-colour in Antirrhinum ma/jus has been worked 

 out by one of us* and also by Baur.f Investigation has shown that the 

 flower-colour of the type in Antirrhinum is due to the presence of at least 

 six factors and that these, in various combinations, produce a series of colour- 

 varieties. Full accounts of the factors have been given in the papers cited, 

 but for convenience of reference four are mentioned again here, i.e. : — 



Y. A factor representing the power to form ivory pigment in the tube', 



accompanied by yellow pigment in the lips. 

 I. A factor representing the power to form ivory pigment in the lips. 

 R. A factor representing the power to form red pigment in the flower. 

 B. A factor representing the power to convert red into magenta pigment. 



The factorial constitution of the type and varieties can be expressed as 



follows : — 



YY(y)iirrB(b)B(b) Yellow. 



YY(y)II(i)rrB(b)B(b) Ivory. 



YY(y)iiRR(r)bb Bronze. 



YY(y)II(i)RR(r)bb Red. 



YY(y)iiRR(r)BB(b) Crimson. 



YY(y)II(i)RR(r)BB(b) Magenta. 



yyI(i)I(i)R(r)R(r)B(b)B(b) ... White. 



In 1909 a series of researches was commenced with a view to the inter- 

 pretation of the above factors in terms of chemical substances, or possibly 



* Wheldale, M., "The Inheritance of Flower-colour in Antirrhinum majus," ' Eoy. Soc. 

 Proc.,' 1907, B, vol. 79, p. 288 ; " Further Obsei'vations on the Inheritance of Flower- 

 colour in Antirrhinum majus" ' Rep. Evol. Com. Boy. Soc.,' V, 1909, p. 1. 



t Baur, E., " Einige Ergebnisse der experimentellen Vererbungslehre," ' Beihef te zur 

 Med. Klinik,' Berlin, 1908, Heft 10, p. 265 ; " Vererbungs- und Bastardierungsversuche 

 mit Antirrhinum," 'Zs. indukt. Abstammungslehre,' Berlin, 1910, vol. 3, p. 34. 



