Which organism did Thomas Hunt Morgan use to establish the Chromosomal Theory of Inheritance?

• A. Drosophila melanogaster
• B. Mus musculus
• C. Caenorhabditis elegans
• D. Apis mellifera

Answer: (A)

The main idea here is that Thomas Hunt Morgan established the Chromosomal Theory of Inheritance using a highly tractable genetic model. He chose the fruit fly, Drosophila melanogaster, because its life cycle is fast, it produces many offspring, and scientists can easily observe visible mutations across generations. These traits allowed him to track how genes assort, recombine, and map to specific chromosomes. In particular, Morgan found that a sex-linked trait behaved according to chromosome-based inheritance on the X chromosome, which provided powerful evidence that genes reside on chromosomes and are inherited in a Mendelian fashion when their chromosomal behavior is accounted for. While other organisms like the mouse, C. elegans, or the honeybee are all important in genetics today, Morgan’s classic demonstration that linked genes lie on chromosomes came from his work with Drosophila melanogaster.