George Washington Carver and Nettie Stevens

George Washington Carver

• Carver was an African American scientist who helped restore the Southern economy by developing farming practices and cultivating crops besides cotton.
• He developed over 400 products derived from peanuts and sweet potatoes, boosting financial yields and making the South a key contributor to the US agricultural industry.
• Carver, the first African American to enroll at Iowa State Agricultural College, studied agriculture and obtained a degree in 1894.
• As Director of Agriculture at Tuskegee Institute, he advocated for the use of peanuts, sweet potatoes, and soybeans, crops that were nitrogen-rich and helped restore the soil.
• His work was recognized and received a standing ovation from the US House of Representatives in 1921, earning him the Spingarn Medal in 1923.

Nettie Stevens

• Stevens was an early 20th-century biologist who made the groundbreaking discovery of animal sex determination.
• She refuted the belief that external factors like temperature or nutrition determined sex, proving that sex was instead determined by chromosomes.
• Her research involved studying the reproductive cells of mealworms under a microscope, which led to the discovery that male reproductive cells contained X and Y chromosomes, while females produced only Xs.
• These findings were published in 1905, just before US geneticist Edmund Beecher Wilson, and established the first link between a physical characteristic and a particular chromosome.
• Stevens’s work, though initially overshadowed, is now recognized as crucial in the field of genetics.

Thomas Hunt Morgan

• An eminent geneticist who won the Nobel Prize for his groundbreaking work on heredity.
• His research confirmed the role of chromosomes and laid the foundation for modern genetics.
• Morgan was instrumental in proving Mendel’s laws of inheritance by observing how physical characteristics are passed down through generations.
• He established the “Fly Room” laboratory at Columbia University in 1908, which specialized in raising fruit flies for genetic studies.
• By breeding millions of fruit flies with specific traits, Morgan observed how physical traits were passed down through generations, confirming that genes occupy a specific location on a chromosome.

Hermann Joseph Muller

• An American geneticist who received a Nobel Prize for his work on genetic mutations, showing that hereditary changes can be induced through X-rays.
• Muller worked in the field of genetics for 12 years at the University of Texas, where he investigated genetic mutations for 12 years.
• In 1926, he conducted experiments that proved his theory by using X-rays to induce mutations.
• Muller became a pioneer in highlighting the long-term dangers of human exposure to radiation and campaigned for controls on nuclear weapons.