Mendel, a priest born on July 20, 1822 in Brunn, Austria (now Brno, Czech Republic), is the founder of genetics and is known as the father of modern genetics. Through pea experiments, he discovered two of the three basic laws of genetics, namely the law of separation and the law of free combination.
Mendelian law of inheritance
The formation and development of any subject is always closely related to the outstanding figures who were keen on this scientific research at that time. The formation and development of genetics are no exception. Mendel was the outstanding founder of genetics. He revealed two basic laws of genetics-the law of separation and the law of free combination.
Meaning
Mendel's laws of separation and free combination are the most basic and important laws in genetics, and many genetic laws discovered later were based on them. It is like a beacon, illuminating the future of modern genetics.
1. theory is applied
Theoretically speaking, the law of free combination provides an important theoretical basis for explaining the diversity of organisms in nature. As we all know, there are many reasons for biological variation, but the free combination of genes is an important reason for the diversity of biological characteristics. For example, if a pair of organisms with 20 pairs of alleles located on 20 pairs of homologous chromosomes are crossed, there are 220=1048576 possible phenotypes in F2. This can explain why the world's biological species are so diverse. Of course, the reasons for biological diversity also include genetic mutations and chromosomal mutations, which will be discussed later.
The law of segregation is due to the fact that some genetic diseases are controlled by recessive genetic factors, and these genetic diseases rarely occur under normal circumstances.
2. Practical application
An important application of Mendel's laws of inheritance in practice is in plant cross-breeding. In the practice of cross breeding, the excellent characteristics of two or more varieties can be purposefully combined, and then self-fed, and continuously purified and selected to obtain a new variety that meets the ideal requirements. For example, there are two varieties of tomato: one is a disease-resistant, yellow-flesh variety, and the other is a disease-susceptible, red-flesh variety. It is necessary to cultivate a new variety that is stable and resistant, and also has red flesh. variety. You can cross these two varieties of tomatoes, and in F2 a new variety that is both disease-resistant and has red flesh will emerge. Use it as a seed to reproduce. After selection and cultivation, you can get the new tomato varieties you need that can be stably inherited.