What is Mendelian genetics?

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Gametes and Phenotypes: Image of Mendelian Genetics

Mendelian genetics (or Mendelian inheritance or Mendelism) is a theory of genetic inheritance which was developed by Gregor Mendel. Genetics is the study of biological inheritance. Mendelian Genetics is widely regarded as the corner stone of classical genetics. It is a set of primary beliefs relating to the transmission of hereditary characteristic from parent organisms to their offspring; it underlies much of genetics. Off spring is the product of You do not have access to view this node, a new organism produced by one or more parents.

 

What is the History of Mendelian genetics?

The laws of inheritance were derived by Gregor Mendel, a 19th century Austrian monk, while conducting hybridization experiments in garden peas. Between 1856 and 1863, he cultivated and tested some 29,000 pea plants. From these experiments, he deduced 2 generalizations which later became Mendel’s Principles of Heredity or Mendelian inheritance. Mendel’s conclusions were largely ignored by many biologists of that time. He did not get everything quite right, but he got very close. Mendel’s work was re-discovered in early 1900s. Later, when they were integrated with the chromosome theory of inheritance, a fundamental unifying theory of genetics emerged, which was proposed by Thomas Hunt Morgan in 1915. Those principles became the core of classical genetics.

 

What are Mendel's laws?

At the time of Mendel’s research, there wasn't a whole lot of knowledge available about genetics. Mendel came up with an idea which was innovative for the time: creating a pure genetic line for research and recording his results carefully. He chose peas for his experiments, because they grow quickly and are easy to hybridize; and along the way he made a number of notable discoveries, formulating 2 laws of genetics which were not very famous / popular with the scientific community of that time. The laws are as follows

  • Law of Segregation: This law stated that each organism inherited half of its genetic material from one parent and half from the other. That is, the two members of a gene pair (alleles) separates from each other in the formation of gametes (sex You do not have access to view this node). Half the gametes carry one allele, and the other half carries the other allele. The direct proof of this was later found following the observation of meiosis (type of cell division for sexual You do not have access to view this node) by 2 independent scientists, the German botanist, Oscar Hertwig in 1876, and the Belgian zoologist, Edouard Van Benden in 1883.
  • Law of Independent Assortment: The principle of this law states that the alleles for a trait (distinguishing feature of personal nature) separate when the gametes (sex You do not have access to view this node) are formed. An allele is an alternative form of a gene that is located at a specific position on a specific chromosome. These allele pairs are then randomly united at fertilization. Traits are transmitted to off springs independently of one another. So, the law stated that the traits manifested independently from each other, and the other traits could be divided into dominant and recessive categories.
  • But what Mendel did not realize was that some genetic traits actually involve multiple locations which interact with each other, like eye color. Although, Mendel’s conclusions were not totally perfect, the concept of the Mendelian genetics still astonished the scientific community. His theory explained why traits can remain hidden for generations, which ran against popular theories which suggested that traits were inherited continuously. The idea of inheriting genetic material equally from both parents was made fun, thanks to the fact that microscopes were not advanced enough to detect the process of meiosis.

 

What is Mendelian Traits?

In the early 20th century, several scientists referenced his work, building upon the basic concepts of Mendelian genetics and adding their own concepts and ideas to create the theory of classical genetics. In honor of Gregor Mendel, traits which are determined by genes at a single location are known as Mendelian traits.

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