In 1900, Mendel’s work was rediscovered by:
1. | Khorana, Nirenberg and Mathei |
2. | de Vries, Correns and von Tschermak |
3. | Avery, McCleod and McCarty |
4. | Watson, Crick and Wilkins |
“Chromosomes, which are seen in all dividing cells and pass from one generation to the next, are the basis for all genetic inheritance”.
This statement is credited to:
1. | Watson and Crick | 2. | Hershey and Chase |
3. | Sutton and Boveri | 4. | Meselson and Stahl |
The two alleles of a gene pair are located on:
1. | The same chromosome. |
2. | Different chromosomes. |
3. | Homologous sites on homologous chromosomes. |
4. | Homologous sites on heterologous chromosomes. |
T. H. Morgan worked on the fruit fly, Drosophila melanogaster. Which of the following is not an advantage of this fly?
1. | They could be grown on a simple synthetic medium in the laboratory. |
2. | They complete their life cycle in about two years, and a single mating could produce a large number of progeny flies. |
3. | There was a clear differentiation of the sexes – the male and female flies are easily distinguishable. |
4. | It has many types of hereditary variations that can be seen with low-power microscopes. |
When Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F1 progeny, the F2 ratio deviated very significantly from the 9:3:3:1 ratio. This can be attributed to the fact that:
1. | The genes are located on the X and Y chromosomes. |
2. | Fruit fly has abnormal chromosomes. |
3. | The genes are located on the X chromosome. |
4. | The genes exhibit incomplete dominance. |