TS Inter 2nd Year Botany Notes Unit 3 Genetics

Here students can locate TS Inter 2nd Year Botany Notes Unit 3 Genetics to prepare for their exam.

TS Inter 2nd Year Botany Notes Unit 3 Genetics

→ The biological science that deals with the study ofheriditary and variation is known as Genetics.

→ Gregor Johann Mendel proposed the ‘laws of inheritance’ those led down foundation of the Genetics through his famous hybridization experiments on Phisum sativum.

→ Law of segregation states, that “the two alleles of a gene present together in het-erozygous state, do not fuse, remain distinct and segregate during meiosis.

→ Law of independent assortment states that “Genes for different characters are inherited independently of one other”.

→ The dominant characters are expressed when factors are either in homozygous or in heterozygous condition. (law of dominance)

→ The recessive characters are expressed only in homozygous condition. Different com- biriations of gametes are theoretically represented in a square tabular form known as “Punnett square.”

→ A cross involving a F1 individual and any one of its parents is called Back cross.

→ A cross between a F1 individual and its double recessive parents is called Test cross.

TS Inter 2nd Year Botany Notes Chapter 3 Genetics

→ Monohybrid cross: Phenotypic ratio is 3 :1 and genotypic ratio is 1; 2:1.

→ Dihybrid cross: Phenotypic ratio is 9:3:3:1 and genotypic ratio is 1:2:2:4:1:2 : 1:2:1.

→ Mendel’s laws were extended in the form of “Chromosomal theory of inheritance.”

→ Later it was found that Mendel’s law of independent assortment did not hold true for the genes that are located on the same chromosomes. These genes are called linked genes.

→ Closely located genes assorted together and distantly located genes, due to recombi-nation, assorted independently.

→ Mutations involves changes in chromosomes and/or genes. They help to increase variability which might be useful in crop improvement

→ Gregor Johann Mendel:

  • Born: Johann Mendel, July 22, 1822 Heinzendorf bei Odrau, Austrian Empire (Now Hync (ice, czech Republic))
  • Died: January 6,1884 (aged 61) Brno (Brunn), Austria – Hungary (now Czech Republic)
  • Nationality: Empire of Austria – Hungary’
  • Fields: Genetics
  • Institutions: Abbey of St. Thomas in Brno
  • Alma mater: University of Olomouc University of Vienna
  • Known for: Creating the science of genetics

Gregor Johann Mendel laid foundation for the Science of Genetics and Study of Hereditary. 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. In 1 843 Mendel began his training as a priest. Brno Johann Mendel, he took the name Gregor upon entering religious life. In 1851 he was sent to the University of Vienna to study. At Vienna, his professor of physics was Christian Doppler. Mendel returned to his abbey in 1853 as a teacher, principally of physics, and by 1867, he had replaced Napp as abbot of the monastery. During this time he began the experiments for which he is best known. He published the results of his studies under the title “Experiments on Plant Hybrids”

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