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Inheritance: A history of sex, genes and DNA
An animated history of how we arrived at our current understanding of inheritance. Aristotle was the first person to put forward a theory for why children look like their parents. He concluded that the woman provides all the resources to grow a child, while the man provides all the information about its form - like planting a seed. For hundreds of years this remained the only explanation for inheritance. The next big leap forward came in the 17th century when Niels Stensen and Antonie van Leeuwenhoek identified sperm and eggs. But confusion still reigned and as scientists fought amongst themselves over which of these cells was primarily responsible for producing the child. By the 1800s, however, people had begun to think differently. Farmers had shown that by selectively breeding their animals they could produce offspring with a blend of parental characteristics; therefore, children must be a mixture of their parents, inheriting some characteristics from their mothers and some from their fathers. The first plausible mechanism for how this might happen came from an Austrian monk, Gregor Mendel, who had spent years carefully breeding pea plants in the grounds of his monastery. He noticed that offspring received instructions from both parents, but some traits were dominant and some recessive. Still nobody knew where all the information needed to create a child was stored. The answer finally came at the start of the 20th century; a scientist called Thomas Morgan identified the origin of the inheritable material as tiny structures inside the cell called chromosomes. Scientists began to unravel the chromosomes until Crick and Watson added the final piece of the inheritance puzzle by solving the structure of DNA. First broadcast on 'Dara O Briain's Science Club' on BBC Two in November 2012.
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