Many questions regarding the nature of inheritance have captured the interest of many scholars and researchers for many centuries. The earliest theories proposed to explain such mystery of nature mirrored the lack of scientific equipment and methodologies by which the early scientists could investigate their world in fine detail, as well as the strength of religious principles and myths in the social order in which they live. An example is the early idea on the origin of life, which says it was created spontaneously. Common observations during that time supported this theory of “spontaneous generation” (Levine and Miller, 1994). Scientists without the aid of microscopes observed that maggots suddenly appear on raw meat that showed no previous evidence of infestation. Had microscope available, they would have revealed the presence of tiny insect eggs. In another circumstance, the theory of “preformation” proposed that an entire miniature individual resided in the germ cell and had only to grow in the woman’s womb. However, how the parents passed traits to this embryo was not understood, only that somehow there was a transmission of some aspects of the parents’ bodies to the “homunculus” (Pai, 1974). Many of their theories appear ludicrous today, but each nonetheless served to advanced knowledge a step, if not by its own contribution, then by stimulating studies in the right direction.
It is not surprising that to explain the origin of variations, people sought answers in terms of magic, folklore, gods and spirits. Perhaps the earliest most reasonable interpretation of the phenomenon of inheritance came from the ancient Greeks, when a writer of the Hippocratic school of medicine, which flourished around 400 B.C., suggested a mechanism for variation remarkably like the one Darwin and Lamarck would proposed some 2200 years later. He surmised that the environment could direct variation along a specific pathway - a belief later referred to as the “theory of acquired characteristics” (Pai, 1974). Noting the practice of people who bound children’s soft skulls to elongate and point them, the writer deduced that in the course of time the elongated and pointed head became an inherited characteristic because the trait would somehow be transmitted to the semen and in turn be passed on to the next generation (Pai, 1974).
Not long afterward Aristotle (384-322 B.C.), somewhat more cautiously, also suggested that acquired traits could be inherited; he pointed out, however, that although deformed parents occasionally produced deformed offspring, the offspring of cripples were usually of sound body (Jenkins, 1975). He added that their children sometimes resemble their grandparents rather than their parents (Jenkins, 1975). Thus without obviously, any idea of the mechanism or even the concept, grasped the common genetic phenomenon of recessiveness. In one form or another, observations and ideas such as these were important forces in biological thought well into the nineteenth century.
Among the views dominating biological thought during the hundred years before Mendel described his findings in 1865, none were more influential than those of the Swedish taxonomist Carl von Linne (Latinized as Carolus Linnaeus, 1707-1778, who is best remembered today for his work on the systematic classification of plants and animals (Jenkins, 1975). Linnaeus held strong anti-experimentalist views, stimulated the kind of research that dealt with the collection and classification of data rather than original investigation (Jenkins, 1975). One prominent idea, which was called the fixity-of-species doctrine and was supported by Linnaeus and his followers, stemmed from the religious belief in special creation, stated that animal and plant species were created by God and remained unchanged and unchangeable (Jenkins, 1975). This doctrine still influenced the interpretation of experiments in plant hybridization conducted over nearly a century with the constraining notion that species had been fixed by special creation, until Mendel announced his findings on variation in pea plants. For over a hundred years, the fixity-of-species concept tended to warp or retard scientific thinking. This doctrine was, however, worn down by the strength of men like Lamarck and Darwin, proposing instead that organisms change over time and new species evolve from preexisting species.
