Genetics is part of biology which study genes, genetic variation in organisms. A gene is made of DNA and it is a type of genetic instruction, these are used to make molecules and scheming the chemical reaction of life. Genes exist in chromosomes, these chromosomes are composed of protein and DNA. The key components in genetics are DNA, RNA, Chromosomes, Genome, Heredity, Mutation, Nucleotide, Variation etc. The major topics and research involved in genetics are Molecular Evolution, Population Genetics, Quantitative Genetics, Molecular Genetics, DNA sequencing, Genetic Engineering, Genomics, Medical genetics.