510 H. NILSSON-EHLE 



change in several Mendelian genes. Through complexniutation arises 

 the bearded speltoid from the normal type, but the genes in question 

 are closely linked, and therefore the possible recombinations, the 

 bearded normal type and the beardless speltoid, as shown l)e the tables 

 2 and 3, are, in the progeny of heterozygotes (fig. 2, b), very seldom 

 formed (chapter IV). 



5. In certain cases of speltoidmutation also a dense-eared sub- 

 compactum-type (fig. 2, f) arises in the progeny of heterozygotes (see 

 table 4). In these cases it is assumed, that through the complex- 

 mutation at least three genes at the same time mutate. The compac- 

 tum-factor is not so closely linked to the other mutated factors as 

 these to each other and arises therefore somewhat more frequently 

 than the under (4) mentioned recombinations (chapter V). 



6. It is probable that the multiple allelomorph in beardless- 

 l^earded ears also is brought about through complexniutation and 

 linkage (chapter VI). 



7. The complexmutations arise simultaneously and are true mu- 

 tations (chapters VII and VIII). 



8. It is discussed, whether the complexmutations and deficiency- 

 mutations of Bridges (1917) and Mohr (1919) are identical phe- 

 nomena (chapter IX). 



9. The existence of complexmutations is in accordance with the 

 wellknown theory of Morgan and co-workers concerning the arrange- 

 ment of the genes in the chromosomes. Through complexmutation 

 genes, who are lying near to each other and more or less closely linked, 

 may simultaneously mutate (chapter X). 



10. The following part of chapter X discusses the significance 

 of complexmutations for the question of > Pleiotropie », for the pre- 

 sumed identity between dominant and recessive characters, for the 

 presence and absence theory and for the question whether mutations 

 in Mendelian genes can be assumed to play any role in evolution. 



LITERATUR. 



1. Bateson, W. 1913. Problems of genetics. Newhaven, London, Oxford. 



2. Baur, E. 1912. Vererbungs- und Bastardierungsversuche mit Antirrhinum. II. 



Faktoren-koppelung. Zeitschr. für indukt. Abst.- und Vererbungslehre, Bd. 

 6, S. 201—216. 



