APPENDIX I 



Differentiation, the process whereby a cell, through mitosis and not 

 through meiosis, produces two daughter cells of immediately or 

 ultimately dissimilar form or function with or without genetic 

 dissimilarity; hence the process by which dissimilar tissues arise within 

 the same individual. The process of differentiation is repeated by 

 heredity and is therefore genetically determined. 



DiGENic, V. Monogenic. 



DiHYBRiD (Diheterozygote), heterozygotc in respect of two genes. 



Diminution, v. Chromosome. 



DiOECY, Haploid or Diploid, the condition in which male and female 

 gametes are borne on separate haploid or diploid individuals respec- 

 tively. Has usually been termed Unisexuality in animals, v. also 

 Heterothally, Sex. 



DiPLOCHROMOSOME, V. Chromosome. 



DiPLOGENOTYPic Sex-Determination, causing Diploid Dioecy. Hartmann 

 1918. 



Diploid, i. The zygotic number of chromosomes {211) as opposed to 

 the gametic or Haploid number (»). Strashurger 1905. 

 2. An organism having two sets of chromosomes {ix) as opposed 

 to organisms having one (Haploid), three (Triploid) or more 

 sets (.V, 3.V, etc.). 



Diploidization, process of fusion of hyphae followed by division of 

 nuclei in pairs in fungi, whereby haploid cells or myceha become 

 diploid. BuUer 1930. 



Diplont, organism at the diploid stage of the hfe-cycle, as opposed to 

 Haplont at the haploid stage. 



Diplophase, the diploid stage (as opposed to the haploid, Haplophase) 

 of the life history in plants with an Alternation of Generations, 

 especially in Basidomycetes and higher Ascomycetes where the 

 nuclei do not fuse when the hyphae become diploid, Vuillanin, 

 Goebel. 



Diplotene, the stage of meiosis which follows division of the chromo- 

 somes and chiasma formation at the pachytene stage, von Winiwarter 

 1900. 



Discriminant Function, linear compoimd of a series of variates, obtained 

 by giving the different variates individual coefficients such as will 

 maximize the differences between the classes, relative to the 

 variation witliin classes, of objects of which the variates are 

 measurements. 



Disjunction, the separation of chromosomes at anaphase, particularly 

 of the first meiotic division, v. Non-Disjunction. 



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