APPENDIX I 



EucHROMATiN, V. Chromatin. 



Eugenic, that which tends to increase the fitness of the race. 



Eugenics, the study of the means of producing eugenic changes, or 



avoiding dysgenic changes, in man. Galton 1883. 

 EuPLOiD, having all Chromosomes of the Set present in the same number. 



Cf. Aneuploid. Tackholm 1922. 

 Ever-Sporting, producing frequent Sports. Especially applied to a 



heterozygote which segregates homozygous recessives, but not 



homozygous dominants, in every generation, e.g. doubleness in 



Stocks, f . Unfixable. Bateson, Punnett and Saunders 1906. 

 Exaggeration, of the expression of a hypomorphic gene placed opposite 



a deficiency. Mohr 1923. 

 Exceptions, Primary, Secondary and Equational, individuals showing 



by their character the consequences of Primary, Secondary, and 



Equational Non-Disjunction in their parents. Bridges 1916. 

 Exogamy, Outbreeding. MacLennan 1865. 

 Expressivity (of a gene), the degree of manifestation of a genetic effect 



in those individuals in wliich it is detectable. Timofeeff-Ressovsky 



1931- 

 Extension Factors, genes which increase the expressivity of other genes. 



Applied to area of pigmentation. 



Fj, the first generation of the cross between two individuals homozygous 

 for the particular genes which distinguished them. Mendel 1865. 



F2, the second fJial generation obtained by self-fertilizing or crossing 

 inter se individuals of an Fj. Mendel 1865. 



F3, progeny obtained by self-fertilization of an Fg individual. (Inter- 

 crossing two F2 individuals gives a biparental progeny of the third 

 generation, not an F3.) 



Factor, that which is responsible for the independent inheritance of a 

 mendehan difference, v. Gene. Mendel 1865. 



Factorial Experiment, one in which all the treatments or agents under 

 investigation are varied simultaneously, and combined in such a way 

 that any derived effect of one or a group of them may be isolated 

 and separately evaluated. 



Female, v. Sex. 



Fertilization, the fusion of male and female gametes and of their nuclei, 

 without which their later development is usually impossible. 

 Cross-Fertilization (Crossing), the fusion of male and female 

 gametes from different haploid or diploid individuals, 



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