Morgan’s Experiment With Drosophila

Thomas Hunt Morgan’s experiments with Drosophila melanogaster, commonly known as the fruit fly, played a pivotal role in advancing our understanding of genetics and the principles of inheritance and variation. Morgan’s work is often referred to as the “fly room” experiments, conducted at Columbia University in the early 20th century.

An overview of Morgan’s experiments and their significance in the field of genetics:

1. Choice of Drosophila as the Model Organism:

Morgan chose Drosophila for his experiments due to its several advantages:

Short generation time.

High reproductive rate.

Easily observable and distinguishable traits.

Ability to control mating and genetic crosses.

2. Discovery of Sex-Linked Inheritance:

One of Morgan’s most significant findings was the discovery of sex-linked inheritance. He observed that certain traits, such as eye color, were consistently inherited differently in male and female fruit flies.

He found that the gene for eye color was located on the X chromosome. This discovery provided strong evidence for the chromosome theory of heredity, which proposed that genes are located on chromosomes.

3. Identification of Recombination and Linkage:

Morgan’s experiments also led to the discovery of genetic recombination, specifically the phenomenon of crossing over during meiosis.

By studying the inheritance of multiple traits simultaneously, he observed that some traits that were expected to be inherited together due to their proximity on the same chromosome exhibited independent assortment.

This observation led to the concept of genetic linkage and recombination.

4. Morgan’s Famous White-Eyed Mutant:

Morgan’s most famous experiment involved a white-eyed mutant male fruit fly. In wild-type Drosophila, the eyes are red. However, he discovered a male fly with white eyes, which was a rare mutation.

By carefully breeding this white-eyed mutant, he confirmed that the trait was linked to the X chromosome, as it was passed on to offspring in a sex-specific manner.

5. Confirmation of Mendel’s Laws:

Morgan’s work provided experimental evidence that supported Gregor Mendel’s laws of inheritance. In particular, he demonstrated the principles of dominance, segregation, and independent assortment.

6. Legacy and Impact:

Morgan’s experiments and subsequent research by his colleagues laid the foundation for modern genetics. His work provided crucial insights into the relationship between genes, chromosomes, and inheritance.

He was awarded the Nobel Prize in Physiology or Medicine in 1933 for his contributions to the field of genetics.