Genetic inheritance and variations
Read the following passage carefully and answer the given questions.
While studying the pattern of inheritance in pea plants of contrasting characters, Mendel proposed the principles of inheritance, which are today referred to as ‘Mendel's Laws of Inheritance’. He proposed that some characters are dominant over others. The Punnett square can be effectively used to understand the independent segregation of the two pairs of genes during meiosis and the production of eggs and pollen in the plants. The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis. Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle cell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc. It is important to mention here that such Mendelian disorders may be dominant or recessive. In Sickle cell anaemia the mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure. In thalassemia the formation of abnormal haemoglobin molecules resulting into anaemia which is characteristic of the disease. Thalassemia can be classified according to the affected chain of haemoglobin molecule.
Which one of the following scientists did not independently rediscover Mendel's results on the inheritance of characters?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Reginald C. Punnett
(1) De Vries — Rediscovered Mendel’s results. He was one of the three scientists who did so independently in 1900.
(2) Correns — Rediscovered Mendel’s results. He was one of the three.
(3) Von Tschermak — Rediscovered Mendel’s results. He was one of the three.
(4) Reginald C. Punnett — Did not rediscover Mendel’s results. Punnett was a British geneticist. He developed the Punnett square, a chart that shows all possible genotypes of a cross.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Chromosomal Theory of Inheritance – “… In 1900, three Scientists (de Vries, Correns and von Tschermak) independently rediscovered Mendel’s results on the inheritance of characters.”
Inheritance of One Gene – “… The production of gametes by the parents, the formation of the zygotes, the F1 and F2 plants can be understood from a diagram called Punnett Square as shown in Figure 4.4. It was developed by a British geneticist, Reginald C. Punnett.”