The Plant journal: for cell and molecular biology. 2003; 36 (5):629–42. [ PubMed ] Articles from PLoS ONE are provided here courtesy of Public Library of Science.
• • • The history of genetics dates from the with contributions by,. Modern biology began with the work of the. On pea plants, published in 1866,what is now. Some theories of suggest in the centuries before and for several decades after Mendel's work. The year 1900 marked the 'rediscovery of Mendel' by, and, and by 1915 the basic principles of Mendelian had been applied to a wide variety of organisms—most notably the fruit fly.
Led by and his fellow 'drosophilists', geneticists developed the model, which was widely accepted by 1925. Alongside experimental work, mathematicians developed the statistical framework of, bringing genetic explanations into the study of. With the basic patterns of genetic inheritance established, many biologists turned to investigations of the physical nature of the. Installshield cab file viewer 140 1. In the 1940s and early 1950s, experiments pointed to as the portion of chromosomes (and perhaps other nucleoproteins) that held genes.
A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of. In the following years, chemists developed techniques for sequencing both nucleic acids and proteins, while Joe Walsh worked out the relationship between the two forms of biological molecules: the.
The regulation of became a central issue in the 1960s; by the 1970s gene expression could be controlled and manipulated through. In the last decades of the 20th century, many biologists focused on large-scale genetics projects, sequencing entire genomes. Of transmission of movements from parents to child, and of from the father.
The model is not fully symmetric. The most influential early theories of heredity were that of and e. Hippocrates' theory (possibly based on the teachings of ) was similar to Darwin's later ideas on, involving heredity material that collects from throughout the body. Instead that the (nonphysical) of an organism was transmitted through semen (which he considered to be a purified form of blood) and the mother's menstrual blood, which interacted in the womb to direct an organism's early development. For both Hippocrates and Aristotle—and nearly all Western scholars through to the late 19th century—the was a supposedly well-established fact that any adequate theory of heredity had to explain. At the same time, individual species were taken to have a; such inherited changes were merely superficial. The Athenian philosopher observed families and proposed the contribution of both males and females of hereditary characters ('sperm atoms'), noticed dominant and recessive types of inheritance and described segregation and independent assortment of 'sperm atoms' In the of 300CE, ancient Indian medical writers saw the characteristics of the child as determined by four factors: 1) those from the mother’s reproductive material, (2) those from the father’s sperm, (3) those from the diet of the pregnant mother and (4) those accompanying the soul which enters into the fetus.
Each of these four factors had creating sixteen factors of which the of the parents and the soul determined which attributes predominated and thereby gave the child its characteristics. In the 9th century CE, the writer considered the effects of the on the likelihood of an animal to survive. In 1000 CE, the, (known as Albucasis in the West) was the first physician to describe clearly the hereditary nature of in his. In 1140 CE, described dominant and recessive genetic traits in. Plant systematics and hybridization [ ].