THE FATHER OF GENETICS: Gregor Mendel

GEORGE MENDEL 

Background Information:
Johann George Mendel (1822- 1884)

He was one of the earliest scientists involved in genetic research. He developed some of the fundamental principles of genetics by conducting his research using peas for approximately 8 years, which was later burnt by monks.  His research deduced the following main laws about inheritance in relation to genetics:

1.     The law of dominance: An organism that contains two sets of genes will always express the stronger set of genes

2.     The Law Of Segregation: Offspring inherit one gene from each parent as a result of the fusion between the two gametes during fertilization.

3.     The Law Of Independent Assortment: The inheritance of one gene is not independent of another because genes for different traits are separated from one another.

He was able to deduce the mentioned conclusions by carrying out experiments using pea plants. This involved selectively cross-pollinate purebred plants with specific traits and observe this outcome across the span of several generations down the line. His research also led to the discovery of recessive and dominant alleles as mentioned in the law of dominance. 

The above illustration is a visual representation of the three main law created by Mendel. The homozygous or pure breed parent plants pass down each gene to their offspring. This establishes their offspring as heterozygous (containing both alleles) as they all inherit one gene from each parent plant.  The f1 generation ( a loose term given towards the first generation of pea plants) have both alleles but express only the dominant. This is due to the fact that the allele that causes the phenotype (physical characteristics off the plant) to be yellow is stronger which causes the recessive gene which is present to be silent (not expressed). In this case, the recessive gene is green. Therefore when the two types of peas are cross breed all of the first generation pea plants will be yellow.

The f2 (second generation) of pea plants when cross bred with one another are capable of producing offspring that can either be yellow or green. This is known as monohybrid crossing. The offspring can either be yellow or green because they possess different combinations of the parent generation genes.