The chromosomal basis of inheritance
- Boveri and Sutton's chromosome theory of inheritance states that genes are found at specific locations on chromosomes, and that the behavior of chromosomes during meiosis can explain Mendel’s laws of inheritance.
- Thomas Hunt Morgan, who studied fruit flies, provided the first strong confirmation of the chromosome theory.
- Morgan discovered a mutation that affected fly eye color. He observed that the mutation was inherited differently by male and female flies.
- Based on the inheritance pattern, Morgan concluded that the eye color gene must be located on the X chromosome.
The chromosome theory of inheritance
- Chromosomes, like Mendel's genes, come in matched (homologous) pairs in an organism. For both genes and chromosomes, one member of the pair comes from the mother and one from the father.
- The members of a homologous pair separate in meiosis, so each sperm or egg receives just one member. This process mirrors segregation of alleles into gametes in Mendel's law of segregation.
- The members of different chromosome pairs are sorted into gametes independently of one another in meiosis, just like the alleles of different genes in Mendel's law of independent assortment.