key term - Thomas Hunt Morgan

Definition

Thomas Hunt Morgan was an American geneticist known for his pioneering work in the field of genetics, particularly in understanding the role of chromosomes in heredity. He conducted crucial experiments with the fruit fly Drosophila melanogaster, demonstrating that genes are located on chromosomes and laying the groundwork for the chromosomal theory of inheritance, which connects closely to the mechanisms of genetic variation observed during meiosis.

5 Must Know Facts For Your Next Test

1. Morgan received the Nobel Prize in Physiology or Medicine in 1933 for his discoveries concerning the role played by chromosomes in heredity.
2. His work established that traits can be mapped to specific locations on chromosomes, allowing for the concept of gene linkage.
3. Morgan's experiments revealed that crossing over during meiosis can lead to genetic variation, as it allows for recombination of alleles between homologous chromosomes.
4. He introduced the idea of sex-linked traits after observing that certain characteristics were inherited differently between male and female fruit flies.
5. Morgan's findings set the stage for future genetic research and greatly influenced the fields of genetics, evolution, and molecular biology.

Review Questions

• How did Thomas Hunt Morgan's experiments with Drosophila melanogaster contribute to our understanding of genetic inheritance?
  • Morgan's experiments with Drosophila melanogaster allowed him to demonstrate that genes are located on chromosomes. By observing patterns of inheritance in fruit flies, he was able to show how traits were linked to specific chromosomes and influenced by crossing over during meiosis. His work provided strong evidence for the chromosomal theory of inheritance, fundamentally changing how scientists understand genetic variation.
• Discuss the significance of Morgan's discovery regarding sex-linked traits and how this impacted the understanding of heredity.
  • Morgan's discovery of sex-linked traits revealed that some characteristics are inherited differently based on an organism's sex. By studying fruit flies, he found that certain traits were only expressed in one sex, leading to a deeper understanding of how genes are transmitted through generations. This finding highlighted the complexity of genetic inheritance and opened up new avenues for research into how sex influences genetic expression.
• Evaluate how Thomas Hunt Morgan's work laid the groundwork for modern genetics and its implications for our understanding of evolution.
  • Morgan's work fundamentally transformed the field of genetics by establishing a clear link between genes and chromosomes. His discoveries regarding genetic linkage and crossing over provided essential insights into how genetic diversity arises within populations. This understanding has crucial implications for evolutionary biology, as it helps explain how traits are passed down through generations and how populations adapt over time. Morgan's legacy continues to influence modern research in genetics, molecular biology, and evolutionary theory.

Related terms

Drosophila melanogaster: A species of small fruit fly widely used as a model organism in genetic research due to its quick generation time and easily observable traits.

Chromosomal Theory of Inheritance:

The theory stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.

Genetic Linkage: The tendency of genes located close together on a chromosome to be inherited together, which was demonstrated through Morgan's experiments.