Selection of subjects.?Observations were made on 100 healthy normal medical students (75 boys and 25 girls) between the ages of ]8 and 26 years. A thorough clinical examination of the subjects was done and those indicating actual disease or a suspicion of disease were discarded. The cases showing high B.S.R. were examined by specialists and some were screened and z-rayed so as to exclude the po...

The ability of a single genotype to generate different phenotypes in disparate environments is termed phenotypic plasticity, which reflects the interaction of genotype and environment on developmental processes. However, there is controversy over the definition of plasticity genes. The gene regulation model states that plasticity loci influence trait changes between environments without alterin...

We have analyzed two Arabidopsis strains differing in the mean seed size and seed number they produced. The accession Cape Verde Islands (Cvi) yielded on average about 40% fewer seeds than the laboratory strain Landsberg erecta (Ler), but Cvi seeds were almost twice as heavy. Maternal and nonmaternal genetic factors were involved in the seed size variation, and interactions between both types o...