APPENDIX I 



Chromatin (continued) 



Classifiable into [Heitz 1929) :— 



EuCHROMATiN, part of the chromatin having its maximum nucleic 



acid attachment on the mitotic spindle. 

 Heterochromatin, any chromatin differing from euchromatin in its 

 nucleic acid cycle. 

 Chromocentre, a body produced by fusion of the heterochromatin of 

 the chromosomes in a resting nucleus. Especially applied to the 

 Polytene chromosomes o( Diptera. Painter 1935. 

 Chromomeres, the smallest particles identifiable by their characteristic 

 size and position in the chromosome thread between leptotene and 

 pachytene and in polytene nuclei. Wilson 1896. 

 Chromonema, the Chromosome Thread. Similarly leptonema, pachy- 

 nema, etc., are the chromosome threads at leptotene, pachytene, etc. 

 Wilson 1896. 

 Chromosome, i. One of a group of bodies in the cell undergoing a 

 co-ordinated cycle of reproduction, Spiralization and charging with 

 Desoxyribose Nucleic Acid. 



2. One of the bodies into which the nucleus resolves itself at the 

 beginning of mitosis and from which it is derived at the end of 

 mitosis. Waldeyer 1888. 

 Chromosome Arm, one of the two parts into which an intercalary 



centromere divides a chromosome. 

 Chromosome Complement, the group of chromosomes derived from 

 a particular nucleus in gamete or zygote, composed of one, two or 

 more sets. Darlington 1932. 

 Chromosome Diminution, the loss or expulsion of a part of the 

 chromosome complement at meiosis or mitosis so that a daughter 

 nucleus is formed lacking this part. Herla 1895. 

 Diplo-Chromosome, a chromosome which has divided twice instead 

 of once since the preceding effective mitosis, its centromere being 

 undivided. White 1935. 

 Chromosome Elimination, diminution which occurs at meiosis alone. 



Seiler and Haniel 192 1. 

 Chromosome Fragmentation, the breakage of chromosomes, v. 



X-Ray. 

 Chromosome Fusion, the permanent linear attachment of two 



chromosomes. 

 Limited Chromosomes, those found only in certain tissues, including the 

 Germ Track, and eliminated in other tissues. Mvtz 1938. v. Chromo- 

 some Diminution. 



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