Chromosomal theory of heredity
The chromosomal theory of inheritance arises by relating the scientific knowledge of the cell with the experiments carried out by Mendel. Its main postulates are:
- The genes that determine the hereditary factors of the phenotype are located on the chromosomes.
- Each gene occupies a specific place or locus (in the plural it is loci) within a specific chromosome.
- Genes (or their loci) are arranged linearly along each chromosome.
- Allele genes (or antagonistic factors) are found at the same locus of the homologous chromosome pair, so that in diploid organisms each trait is governed by a pair of allele genes.
Homologous chromosomes contain identical sets of loci, and genes that occupy homologous loci are antagonistic alleles or factors.
Genes that are very close within the same chromosome tend to be inherited together (linked genes).