APPENDIX I 



Relative Sexuality, the ability of a gamete to act as female when mated 



to one gamete and as male when mated to another. Hartmann 1923. 

 Renner Effect, competition among the four genetically different spores 



formed by one meiosis in regard to which shall form the embryo 



sac. Renner 1921, Darlington ig^i. 

 Replication, the equal incorporation of all combinations two or more 



times in an experimental design, which is then said to be replicated. 

 Reproduction (Self-Propagation), the production of an organism, a 



cell, a chromosome, or any other cell component, by one like itself 



either as parent or sister. 

 Asexual Reproduction (of individuals), that which does not require 



meiosis or fertihzation for its completion, v. Apomixis, Clone, 



Vegetative Propagation. 

 Sexual Reproduction, that wliich requires meiosis and fertilization 



for its completion. 

 SuBSEXUAL Reproduction, Parthenogenesis following Ameiosis in 



which segregation occurs owing to crossing-over but without 



reduction. Darlington 1937. 

 Versatile Reproduction, capacity for either sexual or apomictic 



development of an embryo according to the kind of male gametes, 



owing to variation in pollination, or of female gametes, owing to 



variation in the products of meiosis. Crane and Thomas 1941. 

 Reproduction Rate, v. Malthusian Parameter. 

 Repulsion, v. Coupling. Bateson 1908. 

 Resting Stage of the nucleus, that in which the linear structure of the 



chromosomes is not visible. 

 Restitution, v. X-ray Breakage. 

 Restitution Nucleus, a single nucleus found instead of two through 



failure of the first or second division of meiosis. v. Ameiosis. Rosenberg 



1927. 

 Restraint, a hmitation of the random arrangement of combinations in 



an experimental design so that error variation, while still capable of 



being estimated without bias, is reduced or potentially reduced. 

 Reversion, Atavism. 

 Rings, i. At mitosis, chromosomes with no ends. 



2. At meiosis, chromosomes associated in rings, usually by terminal 



chiasmata, and in twos, fours, sixes, etc. 



Salivary Chromosomes, the chromosomes in the nuclei of the sahvary 



glands of Diptera. v. Polytene. 

 Saltant, mutant of a fungus or bacterium especially in culture. 



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