The Beginnings of Modern Genetics
GENETIC ENGINEERING: THE BEGINNINGS OF MODERN GENETICS
The first scientific investigation of inheritance came from an unlikely place—a monastery garden in what later became Czechoslovakia. There in the 19th century, a monk named Gregor Mendel bred generations of pea plants, observed the way they inherited characteristics, and founded modern genetics. While cell science and evolution theory were advancing, what was happening in inheritance studies? Nothing! Mendel's work was quickly forgotten and not rediscovered until the year 1900. Around the turn of the century, several European scientists unknowingly duplicated Mendel's work. When they realized that he had found the same things 35 years earlier, in the best scientific tradition they quickly named Mendel the founder of modern genetics. By the early 1900s, scientists were using Mendel's laws of segregation and dominance to develop many plants and animals and in order to understand human disease. The next area of investigation concerned what Mendel had called units, or genes. These genes make up what are now called chromosomes. The first major discovery grew out of work on various species of insects. A cell's chromosomes normally come in identical pairs, except for the chromosomes scientists called X and Y. Females always have two X chromosomes. Males of some species have one X and one Y, but in other species males have only a single X chromosome. Scientists quickly realized that the X and Y (or lack of it) determine the individual's sex. But did these chromosomes have other functions as well? The answer came from the first giant of 20th-century genetics, the American Thomas Hunt Morgan. In decades of research with the simple fly Drosophila melanogaster, Morgan and his colleagues and students discovered what the X and Y chromosomes do and Morgan developed the theory of the gene.
Building on Mendel's work, Morgan found that the fly's eye color is transmitted on the X chromosome a red eye is dominant and a
The first scientific investigation of inheritance came from an unlikely place—a monastery garden in what later became Czechoslovakia. There in the 19th century, a monk named Gregor Mendel bred generations of pea plants, observed the way they inherited characteristics, and founded modern genetics. While cell science and evolution theory were advancing, what was happening in inheritance studies? Nothing! Mendel's work was quickly forgotten and not rediscovered until the year 1900. Around the turn of the century, several European scientists unknowingly duplicated Mendel's work. When they realized that he had found the same things 35 years earlier, in the best scientific tradition they quickly named Mendel the founder of modern genetics. By the early 1900s, scientists were using Mendel's laws of segregation and dominance to develop many plants and animals and in order to understand human disease. The next area of investigation concerned what Mendel had called units, or genes. These genes make up what are now called chromosomes. The first major discovery grew out of work on various species of insects. A cell's chromosomes normally come in identical pairs, except for the chromosomes scientists called X and Y. Females always have two X chromosomes. Males of some species have one X and one Y, but in other species males have only a single X chromosome. Scientists quickly realized that the X and Y (or lack of it) determine the individual's sex. But did these chromosomes have other functions as well? The answer came from the first giant of 20th-century genetics, the American Thomas Hunt Morgan. In decades of research with the simple fly Drosophila melanogaster, Morgan and his colleagues and students discovered what the X and Y chromosomes do and Morgan developed the theory of the gene.
Building on Mendel's work, Morgan found that the fly's eye color is transmitted on the X chromosome a red eye is dominant and a