Explain how the Chromosomal Theory of Inheritance helped to advance our understanding of genetics.

Sutton and Boveri proposed what is now known as the chromosomal theory of inheritance in separate papers published in 1902 and 1903. Because it was conceived before there was any direct evidence or confirmation that traits were carried on chromosomes, the chromosomal hypothesis of inheritance was initially disputed. Finally, fruit fly geneticist Thomas Hunt Morgan and his students were able to demonstrate it.

The following examples support the chromosomal theory of inheritance:

• In an organism, chromosomes, like Mendel's genes, are found in matched (homologous) pairs. One member of the pair comes from the mother and the other from the father, for both genes and chromosomes.
• In meiosis, the members of a homologous pair split, and each sperm or egg receives just one of them. The segregation of alleles into gametes in Mendel's law of segregation is mirrored in this process.
• Under meiosis, the members of various chromosomal pairs are sorted into gametes, independently of one another, just as alleles of different genes are sorted into gametes separately from one another in Mendel's law of independent assortment.

The basic premise is that if two genes are located on the same chromosome and you inherit the entire chromosome, you must inherit those two genes (and whatever alleles they include) together.