Alfred Sturtevant facts for kids

Alfred Henry Sturtevant (November 21, 1891 – April 5, 1970) was an American geneticist. He was famous for creating the first genetic map of a chromosome in 1911. Throughout his career, he worked with Thomas Hunt Morgan on the fruit fly, Drosophila melanogaster. He even had a unit of measurement, the sturt, named after him. This unit measures the distance between organs in a developing fly. In 1968, he received the National Medal of Science from President Lyndon B. Johnson.

About Alfred Sturtevant's Life

Alfred Henry Sturtevant was born in Jacksonville, Illinois, on November 21, 1891. He was the youngest of six children. His grandfather was a professor and president at Illinois College, where his father taught math.

When Alfred was seven, his family moved to Alabama to try farming. He went to a one-room schoolhouse before high school. In 1908, he started college at Columbia University. He lived with his older brother, Edgar, who taught him about research.

As a child, Alfred had made family trees, called pedigrees, for his father's horses. In college, he learned about Mendelism. This was a new idea that explained how traits are passed down. It helped him understand the horse pedigrees. His professor, Thomas Hunt Morgan, encouraged him to write a paper about his findings. Alfred finished his PhD with Morgan in 1914.

After his PhD, Sturtevant stayed at Columbia. He joined Morgan's research team in the "fly room." This was a special lab where big discoveries were made using fruit flies. In 1922, he married Phoebe Curtis Reed. They had three children.

In 1928, Sturtevant moved to Pasadena, California. He became a Professor of Genetics at the California Institute of Technology (Caltech). He stayed there for the rest of his career. He taught genetics to college students and wrote a textbook. He led a new genetics research group at Caltech. In 1949, he became a member of the American Academy of Arts and Sciences. He received the John J. Carty Award in 1965. In 1968, he got the National Medal of Science for his important work in genetics.

Sturtevant was also interested in how living things are classified. He loved solving puzzles, and he saw genetics as a big puzzle. He read a lot and was interested in many topics. He had an amazing memory. He would plan his papers in his head before writing them down. He had a long and successful career. He passed away on April 5, 1970, in Pasadena, California, at age 78.

Genetics Research Before Sturtevant

In 1865, Gregor Mendel published a paper about plant breeding. He introduced the idea of dominant and recessive genes. These ideas explained how traits could skip a generation and then reappear. Mendel also thought that all traits were passed down independently. This was called his law of independent assortment. However, his work was not widely known until 1900.

Between 1865 and 1900, scientists developed new ideas about heredity. In 1883, Wilhelm Roux suggested that the linear shape of chromosomes helped make sure new cells got equal amounts of genetic material. This was an early idea for the chromosome theory. Hugo de Vries also proposed that tiny units of heredity were passed down. He thought these units combined in different ways in offspring.

From 1900 to 1909, scientists found some things that didn't fit Mendel's ideas. Carl Correns reported "gene linkage" in 1900. This meant some genes were passed on together, which went against Mendel's law. Thomas Hunt Morgan was the first to suggest why this happened. He believed that genes passed on together must be located on the same chromosome.

Sturtevant's Big Discoveries in Genetics

Sturtevant made many important discoveries. These include how to create genetic maps, how chromosomes can flip, and the first time a single gene was seen to affect behavior. He also found the first gene defect that could be fixed. His main contribution was his work on "linkage groups." This is a classic way to map chromosomes that we still use today.

In 1913, he showed that genes are arranged in a straight line on chromosomes. He compared them to beads on a necklace. He also proved that each gene for a specific trait has a fixed spot, called a locus.

Between 1915 and 1928, Sturtevant continued his work on Drosophila fruit flies. He confirmed that their genes are in a linear order. In 1920, he published papers showing that two closely related fly species had similar new gene changes. His work also helped explain how sex is determined and how recombination (when chromosomes swap pieces) affects how traits are linked.

One of Sturtevant's most important ideas was that the frequency of crossing-over between two genes could show how close they are on a genetic map. He found that using three genes in a "three-factor cross" gave the most accurate information about gene order. He also showed that "unequal crossing-over" could happen. He thought this might be a key force in evolution.

Sturtevant's work on the Drosophila genome was very important. It helped geneticists map the chromosomes of more complex organisms, including humans. His former research partner, George Beadle, said that modern biochemical genetics started directly from Sturtevant's work.

Key publications

See Scholia for some of his publications.

Reprinted 1962, 1988. , Reprinted, 2001.

Students

• Edward B. Lewis
• Alfred G. Knudson

See also

In Spanish: Alfred Sturtevant para niños