Please can anyone tell me what is "allele" in simple terms..... I am unable to understand what is allele and also what do the terms - homozygus, heterozugus mean?
Alleles are the alternative form of a gene present on homologous chromosomes. They occupy the same position on a chromosome and affecting the same characteristic but in alternative ways. For example a gene responsible for height can have two alleles one is for tallness and other is for dwarfness.
Homozygous is the diploid condition in which the alleles at a given position on chromosome are identical. For example: TT and tt.
Heterozygous is the diploid condition in which the alleles at a given position on chromosome are different. For example: Tt