ABSTRACT
Deoxyribonucleic acid (DNA) is the molecule that contains and transfers genetic information from one generation to the next. DNA molecules, in association with histones and various proteins, are organized to form complex intracellular structures called
Figure 14.1 Schematic representation of the generation of two different progenies by fertilization between two distinct populations of sperm and eggs
Figure 14.2 Series of events occurring during spermatogenesis
‘chromosomes’. Mammalian gametes are the direct products of the reductive division of chromosomes, termed meiosis, and thus contain the haploid number (abbreviated n) of hereditary determinants. Both gametes contribute equally to the genetic make-up of new progeny by transmitting the haploid number (n) of chromosomes to the newly formed diploid zygote (2n) of the next generation. The general mechanisms and genes expressed during spermatogenesis, fertilization and implantation are shown in Table 14.1. DNA contains hereditary information within its helical structure, and also provides the basis for the evolutionary process.
