What Has Been Mendel’s Contribution To Medicine Mendel was an Austrian monk and botanist who discovered how characteristics are inherited. He patiently carried out thousands of experiments on pea plants and studied
the results of cross-fertilization among them. He discovered that inheritance does not
work by blending maternal and paternal characteristics together, instead they are
inherited in pairs. In each pair, only one characteristic is only expressed. Mendel worked
out the basic principles of present-day genetics, but scientist could understand the
significance of his work and rediscover him only in twentieth century.
Three of Mendel’s postulates are, law of unit factor, law of dominance and
recessiveness, and law of segregation. Inherited characters are determined by a pair of
contrasting factors or determinants, and this led to establishment of law of unit factors.
Presently, these determinants that occur in pairs are called allele, and each pair together is
called an allelic pair. They occupy a specific portion of the chromosome in a cell, and
that is known as gene. Thus, gene is the inheritance unit that is responsible for a specific
character in the offspring.
When two alleles are brought together for expression of a trait, only one expresses
itself, and the other remains suppressed. That which is expressed is called dominant, and
the other recessive. This is called law of dominance and recessiveness.
The word segregate means to separate. According to the law of segregation,
during the formation of gametes, the two alleles separate from each other so that each
gamete gets any one of them. It was also shown by Mendel that males and females
contribute to the inherited traits in the offspring equally, and the traits that are acquired
are never inherited.
After Mendel’s theories and laws were way past forgotten, new interests in this
field of science raised questions about the factors or determinants mentioned by him. The
search for answer to these questions led to the discovery of chromosomes and genes. It
also helped Sutton and Boveri to establish the chromosome theory of inheritance.
Combining this theory and Mendel’s law of dominance and recessiveness made the
detection of human genetic disorders easy. It was shown that most of the genetic
disorders, such as, Tay-Sachs disease, sickle cell anemia, etc., are determined by
recessive alleles. However, few of the genetically transmitted diseases are also
determined by dominant alleles. Huntington’s disease is an example of this.
Mendel’s suggestion that there is an unit factor responsible for a specific character,
led to investigations, and this in turn, led to the discovery of DNA or deoxyribonucleic
acid in a chromosome. This DNA started to be considered as unit of life, and almost all
cellular events were able to be explained with the concept of DNA. This and related
research developed the science of Genetics and led the foundation stone of another
science, Biotechnology. Biotechnology, in turn, boosted its growth by development of
recombinant DNA and hybridization technologies.
Biotechnology often seems to be affecting the present age Medicine. By
recombinant DNA technology, which is a derivative of Mendelian concept, the whole
outlook of molecular basis of life and interventions into it has changed. Recombinant
DNA technology has helped in the artificial synthesis of genes, isolation of desired genes
or DNA segments, modification of gene, repairing of defective DNA segments to change
defective phenotype. We can directly correlate this to Mendel’s discovery. According to
Mendel, phenotype or outward appearance of a trait is derived from genotype or genetic
make up of the organism. Recombinant DNA technology has been used for the
production of many medicines, such as, somatostatin, insulin, vitamins, antibodies, or
vaccines to which the present-day medical therapeutics is indebted.
DNA technology can be used in diagnosis of a disease too. It has enabled detection
of carriers of hereditary diseases like, muscular dystrophy, Down’s syndrome, Turner
Gene therapy is an important application of genetic engineering. With this, the
otherwise incurable hereditary diseases can be treated by replacing the abnormal genes
causing a particular disease in the stem cells of bone marrow. Severe combined
immunodeficiency disease has been treated by gene therapy.
One more major contribution of Mendelian science is creation of transgenic
animals. They are of great use to modern Medicine. Hemophilia is a disease where blood
clotting fails. The treatment consists of treating the patients with antihaemophilic factor,
but this would need a lot of donors to donate blood. This problem has been solved by
Mendelian concept that the antihaemophilic factor is synthesized as a result of particular
gene expression. The scientists have created transgenic female sheep with
antihaemophilic factor IX gene, and human antihaemophilic factor can be extracted from
the blood of these sheep.
Thus we can see how a simple observation by Gregor Mendel and the statistical
analysis of those data, even if long ignored by the scientific world, have now created the
basis for two other very big and significant sciences, genetics and biotechnology, and
in that way has boosted the modern medicine. To be honest, the modern medicine is
modern medicine for Mendel’s experiments.