The pns includes the somatic and autonomic nervous systems: somatic nervous system a major component of the peripheral nervous system, which transmits sensory signals to the cns via nerves. www. notesolution. com. What is the genetic basis of psychological science: heredity involves passing along genes through reproduction: the human. Genome project has mapped the approximately 30,000 genes that make up the 23 chromosomal pairs in humans, variations of genes (alleles) are either dominant or recessive. The genome represents the genotype and the observable characteristics are the phenotype. Many characteristics are polygenetic: genotypic variation is created by sexual reproduction: because on half of each chromosome comes from each parent and is randomly joined, there is enormous variation in the genome of the resulting zygote. However, studies focusing on rna offer new hope. Psy100 ch3 genetic and biological foundations: neurons are specialized for communication: neurons are the basic building blocks of the nervous system that receive and send chemical messages.