Here students can locate TS Inter 2nd Year Zoology Notes 6th Lesson Genetics to prepare for their exam.
TS Inter 2nd Year Zoology Notes 6th Lesson Genetics
→ Genetics, a discipline of biology, is the science of heredity and hereditary variations in living organisms.
→ The word ‘Genetics’ is derived from the Greek word genesis which means origin of anything or a beginning.
→ The term Genetics was coined by W. Bateson.
→ T.H. Morgan, contributed to the glory of the science of ‘Genetics’ with his experiments on Drosophila melanogaster the fruit fly.
→ Heredity is the study of transmission of characters from one generation to the next.
→ Variations are defined as the difference in characteristics shown by the individuals of a species and also by the progeny of the same parents.
→ Modern science of genetics only began with the work of Gregor Mendel in the Mid 19th Century.
→ After the rediscovery of Mendel’s work by de Vries, Correns and Tschermak, scientists tried to determine which molecules in the cell were responsible for inheritance.
→ Theory of inheritance or Sutton – Boveri Theory is a fundamental unifying theory of genetics.
→ Experimental verification of the ‘Chromosomal theory of inheritance’ by T.H. Morgan and his colleagues, led to discovering the basis for the variation that sexual reproduction produced.
→ The phenomenon of multiple effects of a single gene is called Pleiotropy.
→ When more than two alleles exist in a population of specific organism, the phenomenon is called multiple allelism.
→ Gregor Mendel
Gregor Johann Mendel (1822 – 1884) was a German – speaking It Silesian scientist and Augustinian friar who gained posthumous fame I as the founder of the new science of genetics. Mendel demonstrated | that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian ^inheritance. The profound significance of Mendel’s work was not recognized until the turn of the 20th century, when the independent rediscovery of these laws initiated the modern science of genetics.
→ Francis Galton
Sir Francis Galton, (1822 -1911), cousin of Douglas Strutt Galton, cousin of Charles Darwin, was an Hnglish Victorian polymath: anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto – geneticist,psychometrician, and statistician. He was knighted in 1909. Galton produced over 340 papers and books. He also created the statistical concept of correlation and widely promoted regression toward the mean. He was the first to apply statistical methods to the study of human differences and inheritance of intelligence, and introduced the use of questionnaires and surveys for collecting data on human communities, which he needed for genealogical and biographical works and for his anthropometric studies. He was a pioneer in eugenics, coining the term itself and the phrase “nature versus nurture”. His book Hereditary Genius (1869) was the first social scientific attempt to study genius and greatness.