Gene

:For the band called Gene, see Gene (band)

History

The existence of genes was first suggested by Gregor Mendel, who, in the 1860s, studied inheritance in pea plants and hypothesized a factor that conveys traits from parent to offspring. Although he did not use the term gene, he explained his results in terms of inherited characteristics. Mendel was also the first to hypothesize independent assortment, the distinction between dominant and recessive traits, the distinction between a heterozygote and homozygote, and the difference between what would later be described as genotype and phenotype. Mendel's concept was finally named when Wilhelm Johannsen coined the word gene in 1909.

Related Topics:
Gregor Mendel - 1860s - Independent assortment - Dominant - Recessive - Heterozygote - Homozygote - Genotype - Phenotype - Wilhelm Johannsen - 1909

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In the early 1900s, Mendel's work received renewed attention from scientists. In 1910, Thomas Hunt Morgan showed that genes reside on specific chromosomes. He later showed that genes occupy specific locations on the chromosome. With this knowledge, Morgan and his students began the first chromosomal map of the fruit fly Drosophila. In 1928, Frederick Griffith showed that genes could be transferred. In what is now known as Griffith's experiment, injections into a mouse of a deadly strain of bacteria that had been heat-killed transferred genetic information to a safe strain of the same bacteria, killing the mouse.

Related Topics:
1900s - 1910 - Thomas Hunt Morgan - Chromosome - Drosophila - 1928 - Frederick Griffith - Griffith's experiment

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In 1941, George Wells Beadle and Edward Lawrie Tatum showed that mutations in genes caused errors in certain steps in metabolic pathways. This showed that specific genes code for specific proteins, leading to the "one gene, one enzyme" hypothesis. Oswald Avery, Collin Macleod, and Maclyn McCarty showed in 1944 that DNA holds the gene's information. In 1953, James D. Watson and Francis Crick demonstrated the molecular structure of DNA. Together, these discoveries established the central dogma of molecular biology, which states that proteins are translated from RNA which is transcribed from DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses.

Related Topics:
1941 - George Wells Beadle - Edward Lawrie Tatum - Metabolic pathway - Oswald Avery - Collin Macleod - Maclyn McCarty - 1944 - 1953 - James D. Watson - Francis Crick - DNA - Central dogma of molecular biology - RNA - Reverse transcription - Retrovirus

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