APPENDIX T 



GLOSSARY 



Accessory Chromosome, Sex Chromosome. McChmg 1902. 



Acentric, of a detached part of a chromatid or chromosome lacking 

 a Centromere. Darlington 1937. 



Acquired Character, variously used for modification of phenotype or 

 genotype, adaptive or non-adaptive, induced by one environment 

 and not by another. 



Acquired Characters, Theory of Inheritance of, that acquired 

 characters arc inlierited and adaptive, and thus account for evolu- 

 tionary change. Lamarck 1801. 



Adaptation, the process, and the result of the process, by which members 

 of a genetic group, either as individuals or as parts of individuals or 

 as groups are fitted to past or present changes in their environment. 

 Adaptation is understood to occur in form and function, and the 

 environment to operate both ecologically and biologically. 



Agamospecies, apomictic species. Turesson 1929. 



Age and Area, Theory of, that the areas of distribution of the members 

 of a group of allied species are correlated with their ages as species 

 in any given region. Willis 1922. 



Allelomorph (Allele), one of two or more dissimilar Factors or Genes 

 wliich on account of their corresponding position in corresponding 

 chromosomes are subject to alternative (mendelian) inheritance. Two 

 factors producing unrelated physiological effects, but apparently 

 inseparable in inheritance, may be taken provisionally as non- 

 allelomorphic, e.g. yellow and scute in Drosophila melaiiogaster. 

 Bate son 1902. 

 Multiple Allelomorph, a member of a series of more than two 

 allelomorphs of one gene in one species. Morgan 1914. 



Allogamy, Cross Fertihzation. 



Allopolyploid, a polyploid whose chromosomes form at meiosis not 

 multivalents, but, so far as their homologies permit, bivalents always 

 in the same way, e.g. a tetraploid with 2.v bivalents or a triploid 

 with X bivalents and x univalents. In a broad sense one approaching 

 this condition as opposed to an Autopolyploid. Special classes are 

 Allotetraploid, Allohcxaploid, etc. Kihara and Ono 1926. 



Allosome, as opposed to Autosome. Sex Chromosome. Montgomery 1906. 



Allosyndesis. I. The pairing in a cross between two polyploids of 

 chromosomes derived from opposite parents. 

 2. Pairing in an Allopolyploid between chromosomes derived from 

 different ultimate diploid ancestors. Opposed to Autosyndesis. 



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