The Chromosomal Theory establishes chromosomes as carriers of genetic material and puts forth the following principles:
- Hereditary traits are transmitted through gametes, the reproductive cells formed by the parents (sperms and ova), acting as a link between parents and offspring.
- Chromosomes within the nucleus of gametes serve as the vehicles for transmitting all hereditary characteristics.
- Chromosomes exist in pairs within somatic or diploid cells.
- During gamete formation, homologous chromosomes pair and segregate independently during meiosis, transforming the diploid state into a haploid condition. Consequently, each gamete carries only one chromosome from each pair.
- Fertilization, the union of sperm and egg, restores the diploid number of chromosomes in the resulting zygote.