SEX CONDITIONS 



(arrhenotoky ) . These males and females from un- 

 fertilized eggs have been termed "impaternate" 

 by Ray Lankaster (1919) to differentiate them 

 from the parthenogenetic virgin mother. Breed- 

 ing tests show that impaternate females are nor- 

 mal diploids. P. W. Whiting (1924a) has ex- 

 plained their production from unfertilized eggs 

 by the assumption that the second maturation 

 division of the oocyte is suppressed. If this 

 assumption is true and the impaternate females 

 occur among the F2 from a cross involving mutant 

 characters, their genotypes, as indicated by 

 their appearance and that of their offspring, 

 are of interest in ascertaining whether the 

 first division of the oocyte from which they 

 were formed was equational or reductional for 

 the locus or loci involved (K. G. Speicher, 

 1934). If the Fl female producing an impater- 

 nate daughter is heterozygous for a recessive 

 factor and the first oocyte division is reduc- 

 tional for the locus of that factor, the impa- 

 ternate daughter will be homozygous for either 

 the recessive or its type allele. If the first 

 oocyte division is equational, the impaternate 

 daughter will be phenotypically wild-type. 

 Breeding tests are necessary to distinguish im- 

 paternate females resulting from an equational 

 division from those receiving the type allele 

 from a reductional division. 



Diploid males of biparental inheritance reg- 

 ularly occur in related stocks. These sterile 

 (or near-sterile) males are diploid, developing 

 like females from fertilized eggs. The haploii 

 Tiales have been called uniparental and azygous 

 in contrast to the biparental zygous males and 

 females. The offspring of these diploid males 



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