No. 642] NATURE OF BUD VARIATIONS 



73 



side of gynandromorphs appearing in such crosses ex- 

 hibited all the dominant autosomal characters whether 

 they came from the maternal or the paternal parent. 

 When the mother had a recessive, mutant gene in one of 

 her autosomes and the father had its dominant, normal 

 allelomorph, the fact that the male side of gynandro- 

 morphs did not have the maternal, recessive autosomal 

 character effectively disposed of Boveri's hypothesis of 

 partial fertilization. On the other hand, when a recessive 

 autosomal gene entered from the father's side and its 

 dominant allelomorph from the mother's side, the fact 

 that the male side of the gynandromorphs did not show 

 the paternal, recessive character likewise eliminated 

 Morgan's earlier hypothesis of polyspermia fertilization. 

 It has been shown, further, from crosses, the parents of 

 which differed in sex-linked characters, that maternal 

 and paternal X chromosomes are eliminated with about 

 equal frequency. 



In certain experiments with Drosophihi. in wliicli a de- 

 termination of the frequency of sox-clir.)iii<)>oiiic clinii- 

 nation was undertaken, it was found thai oiif u> iiaiulro- 

 morph appeared in about every 2,2(»(i nuhvuhials. Snieo 

 only those individuals that start as t'ctnah's uivc tlic kind 

 of gvnandromorphs observi'd in thi >c tot-, it was con- 

 cluded that one case of chroniosonir oliinination omirs 

 in ahont in<livi(hial<. 



( )f tho . \ i.h'iicr fi-uni phant iiialcrial thoiv is the recent 

 acL'onnt 1)\ l-'ro>l ( ) o!' the occui-rt'iicc ot' a bud sport 

 in Mdlllnnhi in which prosuniahly Hnk.d genes have 

 scu'i'coatrd out siniultancoush- in one or more branches, 

 mih'tliis ca-c will rc.|uiro t'urtlicr invrsi i-ation before 

 tlu' manner of its oriuin can be ])ositivi'ly established, it 

 seems ])rohabh^ that it l)eh»nu's to tlie category of somatic 

 c.w. ,f;..,, i.v- ..ii.--uiu.<ni)U' plimination or non-disiunc- 



