A P P L N D I X I 



Recessive, v. Dominance. Mendel 1865. 



Reciprocal, of crosses where the sources of male and female gametes 



arc reversed. Mendel 1865. 

 Reciprocal Translocation, Interchange. 



Recombination, the formation by crossing-over or segregation at meiosis 

 of new combinations of genes with respect to either (i) individual 

 chromosomes or (ii) whole gametes. 

 Reduction, the halving of the chromosome number at meiosis and, 

 by extension, its genetical concomitant of segregation. Weismann 

 1887. 

 Double Reduction, the occurrence of a reductional separation at both 

 divisions of meiosis in regard to particular parts of chromosomes. 

 Possible in some hybrids and polyploids. Hence Equational Excep- 

 tions. Darlington 1929. 

 Gametic Reduction, meiosis immediately before fertiUzation. 

 Reduction Divisions, Meiosis. 



Zygotic Reduction, meiosis immediately after fertiHzation. 

 Reductional Separation, separation of homologous parts of non-sister 

 chromatids at anaphase of one or other meiotic division, as opposed 

 to Equational Separation of sister parts of chromatids. 

 Reduplication, the occurrence of a segment of chromosome twice in 



the same haploid set. v. Structural Change. 

 Regeneration, the growing again of a part of an organ lost by injury. 

 In Bryophyta, the growth of a diploid gametophyte direct from 

 a sporophyte after injury. 

 Regression, i. Galton's Law, that in any population of families the 

 deviation of the mean of the offspring from that of the population 

 is less than the deviation of one specified parent, adjustments being 

 made for sex differences. Gallon 1889. 

 2. The dependence of one variate, termed the dependent, on another, 



termed the independent, variate. 

 Regression Coefhcient, the rate of change of the dependent variate 



on the independent, variate. 

 Regression Line, the straight line or curve showing a regression in a 



co-ordinate representation. 

 Linear Regression, that involving the independent variate to the first 



power. 

 Multiple Regression, regression, usually linear, on two or more 

 independent variates, which may themselves be correlated (also 

 called Partial Regression). 

 Simple Regression, linear regression on one independent variate. 



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