Question

Which law of Mendelian genetics can be considered universal ------.
A. Dominance
B. Codominance
C. Independent assortment
D. Segregation

Answer 1

Hint: Gregor Mendel conducted hybridization experiments on garden pea for 7 years. He proposed the laws of inheritance in living organisms. His experiments had a large sampling size which gave greater credibility to the data that he collected. Also from the confirmation of his inferences from experiments on successive generations of his test plants proved that his result pointed to general rules of inheritance rather than been unsubstantiated ideas.

Complete Answer:
- Mendel proposed three laws of genetics : first law is law of dominance, second law is law of segregation, third law is law of independent assortment.
- According to the law of dominance, characters are controlled by discrete units called factors. Factors occur in pairs. In a dissimilar pair of factors one member of the pair dominates the other. The dominant member of the pair is called dominant. Remember that does not dominate is called recessive.
- Exceptions of the law of dominance are, incomplete dominance and codominance.
- According to the law of segregation, the alleles do not show any blending and that both the characters are recovered as such in the $F_2$ generation though one of these is not seen at the F1 stage.
- Though the parents contain two alleles during gamete formation, the factors or alleles of a segregate from each other such that gamete receives only one of the two factors. So the law of segregation of Mendelian genetics can be considered universal.
- According to the law of independent assortment, when two pairs of states are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters. This law also has exceptions. So it cannot be considered universal.

So the correct answer is (D).

Note: During Mendel’s investigation into inheritance it was for the first time that statistical analysis and mathematical logic were applied to problems in biology.