Index 



Acentric chromatid, 78 



Acentric fragment, 78 



Adaptability, hybrids, 99 



Adaptedness, upper attainable level, 219 



Adaptive evolutionary phenomenon, 173 



Additive gene effects, 168 



Additive genetic variance, 511 



Additivity of heterotic gene effects, 483 



Adenine relation to histidine synthesis, 278 



Adenine requirer, 278 



Agglutination titer, 280 



Albinism, 237 



Alcaptonuria, 237 



Alcohol dehydrogenase, 110 



Alfalfa cross- and self-fertilization, 81 



Alleles, 481 



divergent, 173,458 



fortuitous, 322 



interaction between, 229-30, 234 



of intermediate productivity, 294 



less favorable, role of, 323-24 



pseudo and multiple, 254 



relic, 322 

 Allelic genes, 236, 240 

 Allelism, multiple, 500 

 Aluminum in hybrids, 106 

 American Corn Belt dents, heterosis of, 



138-46 

 Anaphase, 75 



Anaphase I of cell illustrated, 67 

 Anaphase I dyads, 73 

 Anaphase II, 76, 77, 79 

 Anaphase II of cell illustrated, 67 

 Anaphase II monads, 73 

 Angiosperm endosperm, 83 

 Angiosperm ovule, 83 



Angiosperms 



female gametophyte in, 83 



fertilization, 83 



mature ovules, 83 



secondary fertilization, 84 



seed, 82-85 



seed coat, 83 



seed development, 81 



Animal inbreeding, 5-7 

 Anthocyanin, 237-38 



Antibiotic substances, 117 



Antigenic characters, 239, 240 



Antigenic complexes, 253 



Antigenic relationships, 244 



Antigenic specificity, alteration of, 278-80 



Antigenic variants induced by radiation, 



279 

 Antigens, 240, 242, 268 



in cattle, 252-54 



of pneumococci, 254 



Artificial hybrid, 424 



Artificial selection, 219-20 



Asexual reproduction, 47 



Autogenic growth inhibitors, 117 



Autonomous apomicts, 89 



Autonomous organelles of the yeast cell, 



261-62 

 Auxins, 112 



Auxotrophic mutants 



biochemical studies, 275-78 



Edwards technique of growing, 279 



frequencies in S. typhimurium, 271 



kinds in S. typhimurmrn, 272 



methods of inducing, 269 



from radiated lines, 269-70 



of S. typhimurium, 281 

 Auxotrophic organisms, 269 



Auxotrophs 



determination of particular nutrilite re- 

 quired, 270 

 utilization of sulphur compounds, 276 

 Average dominance, estimate of, 497-99 

 Average dominance of genes, estimation of, 

 494^516 



Average hybrid, 291 



Backcrosses, 423 

 Backcrossing, 231, 379, 421 



in maize, 235 

 Bacterial genetics, 267 

 Bacterial mutation, 267 

 Balanced defective, 324 

 Balanced euheterosis, 221-22 



Balanced lethal genes 

 in Capsella grandiflora, 46 

 in Oenotheras, 46 



Balanced polymorphism, 221 



537 



