In modern molecular biology and genetics, the genome is the entirety of an organism’s hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA. Genomes are more than the sum of an organism’s genes and have traits that may be measured and studied without reference to the details of any particular genes and their products. Researchers compare traits such as chromosome number, genome size, gene order, codon usage bias, and GC-content to determine what mechanisms could have produced the great variety of genomes that exist today. Horizontal gene transfer is invoked to explain how there is often extreme similarity between small portions of the genomes of two organisms that are otherwise very distantly related. The present book is an important work on genome and covers much more of the subject. In spite of the comprehensiveness, the subject matter has been presented in such a way that it is easily accessible to the students preparing for the examinations of several universities in India and abroad.
