Gregor Mendel

Mendel discovered the principle behind genetics by studying the inheritance of a single factor in pea plants. The inheritance of single characteristics is called monohybrid inheritance. He bred a pure breeding red pea plant with a pure breeding white pea plant and found that they always produced red flowers (the F1 generation). Mendel called the red characteristic dominant. Then when he bred two red pea plants together, he discovered that the next set of flowers were a mixture of red and white pea flowers (the F2 generation). The ratio of red to white was 3:1. Mendel called the white characteristic recessive. From his experiments Mendel concluded that the peas must carry a pair of factors for each feature. When the seeds where formed, they inherited one factor from each parent at random. We now call these factors genes. Genes occur on pairs of chromosomes. Each different form of a gene is called an allele. We now can show the results of Mendel’s pea plant cross using symbols. The dominant characteristic is given a capital letter and the recessive characteristic is given a lower case letter.

Mendel's observations from these experiments can be summarized in two principles, the Principle of Segregation and the Principle of Independent Assortment. Mendel then came to four important conclusions from the experiments, the inheritance of each trait is determined by “units” or “factors” (now called genes) that are passed on to descendents unchanged. An individual inherits one such unit from each parent for each trait. A trait may not show up in an individual but can still be passed on to the next generation. The genes for each trait separate themselves during gamete production.

Gregor Mendel is so important to modern day science as if it wasn’t for him conducting experiments and making conclusions we may never have discovered the laws of heredity on which the modern science of genetics relies upon. His work led to the discovery of inheritance, dominant and recessive traits, genotype and phenotype, and the concept of heterozygous and homozygous. Unfortunately, Gregor Mendel was not recognized for his work by his fellow scientists at the time he was alive. He found actual proof of the existence of genes, and is considered to be the father of genetics, though his work was relatively unappreciated until the early 1900's. His work was ignored by the larger scientific community partly because it wasn’t published in a widely read journal and partly because it tackled a problem in the physical basis of heredity that few other scientists were concerned about at that time.

Bibliography:

AQA Biology textbook

By Azhar Siddiqui 10LA