Pre-Mendelian experiment
As we know, reproduction in living organisms is done to facilitate the continuity of life. The progeny produced, often resemble their parents in most of the characteristics. This passage or transmission of characters from parents to their offsprings is called Heredity and the process by which characters from one generation to the next is called inheritance. However, all characteristics of offspring are not similar to their parents. Some of them show variations or changes also. These variations signify their own characteristics.
The study genetical of heredity and variation is called genetics. This term was proposed by William Basten's in 1905. The basic principles of genetics were discovered by Mendel in (1822-84). The medal is also known as the 'father of genetics'.
Branches of genetics
Geneticists (the scientists who the process of genetics) often divide genetics into the following three main branches,
(1) Trancemission genetics is also called classics genetics. It involved the transmission of genetic material from one generation to another. it is further subdivided into Mendelian genetics, Morganton genetics (i.e. recombination in all kinds of organisms), non-Mendelian genetics, and mutation.
(2) Molecular and biochemical genetics involve the study of structural and functional aspects of genes at a molecular level.
(3) Population and biometric genetics involve the study of behaviour and effect of genes in various biological populations.
Heredity
It is defined as the transmission of structural, functional and behavioural characteristics from one generation to another. Thus, for a generation, it is the sum of genetic endowment obtained from their parents. Thus, for a generation, it is the sum of generation endowment obtained from their parents. The initiation of genetics work is attributed to Mendel. Genetics can be categorised into Pre-Mendelian, Mendelian and Post-Mendelian eras of working.
Pre-mendelian concepts of inheritance(theories of blending inheritance)
Before the idea of Mendel was accepted, there were many philosophers, thinkers and workers who gave various theory to explain heredity or inheritance. These theories are called Pre-Mendelian concept of heredity. Some of these are as follows,
1.Moist vapour theory Pythagoras (580-500 bc) propose that various body part emit certain vapour, which gets aggregated to form a new individual.
2. Flud theory Empedocles (504-433) through that every part of the body produces a fluid. This fluid then mixes up to form an offspring. Any defect in this fluid result in the formation of defective organs.
3. Preformation theory this was given by Swammerdam (1679) and by Malgiphi (1673). They believe that the Minature form of an individual is already present in the sperm or egg called 'homunculus'. Fertilisation is required and nassory to stimulate its growth.
4. particulate theory Maupertius (1689-1759) Propose that various part of the body produce minute particles for reproduction. An individual is formed when the particles from the male and female unit.
5. Theory of pangenesis Darwin (1868) proposed that each body part produces a gemmule or Pantene. These pangenes carry parental strategies as well as variation. Their aggregation result to form gametes. On fusion, these rise to a new individual.
Pre-Mendelian experiment
Among the workers who performed the experiment before Mendel was a German botanist who works on the tobacco plant.
Other persons who worked on hybridisation before Mendal, include Bartner (1722-1850), Naudin (1815-1899) caught (1799) and goss (1824). but none of these workers was able to rationalise and explain the result which a sure degree of repetitions.