Inheritance & Variation
Terminology i. Character : A visible feature of an organism is a character. e.g. Height, seed colour. ii. Trait : An inherited character and its detectable variant e.g. Tall or dwarf. iii. Factor : It is a unit of heredity, a particle present in the organism which is responsible for the inheritance and expression of a character. (Factor is passed from one generation to the next through gametes). iv. Gene : It is a particular segment of DNA which is responsible for the inheritance and expression of that character. v. Alleles or Allelomorphs: Two or more alternative forms of a gene present at the same loci (positions) of homologous chromosomes and controlling the same character are called as alleles or allelomorphs. vi. Dominant : It is an allele that expresses its trait even in the presence of an alternative allele i.e. in heterozygous condition only. OR The allele that expresses in F, is called dominant. vii. Recessive : The character which is not expressed in F₁ generation is called