Which of the following is the most suitable medium for the culture of Drosophila melanogaster?
1. | Cow dung | 2. | Moist bread |
3. | Agar agar | 4. | Ripe Banana |
Mental retardation in man occurs due to:
1. Loss of one X chromosome
2. Addition of one X chromosome
3. Slight growth in Y
4. Overgrowth in Y
Which of the following is a recessive trait in Pisum sativum?
1. | Yellow pod color | 2. | Axial flower position |
3. | Inflated pod shape | 4. | Violet flower color |
In humans, the condition red-green color blindness is a sex-linked recessive trait. In a family pedigree analysis, you find that two people with normal color vision have a color-blind son. This is possible if the genotypes of the parents are:
1. | XcXc and XcY | 2. | XcXc and XCY |
3. | XCXC and XcY | 4. | XCXc and XCY |
The improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics because:
1. | it revealed new and unanticipated features of Mendel’s pea plant varieties. |
2. | it allowed biologists to study meiosis and mitosis, revealing the parallels between the behaviors of genes and chromosomes. |
3. | it allowed scientists to see the DNA present within chromosomes. |
4. | it led to the discovery of mitochondria. |
The salivary gland chromosomes in the dipteran larva, are useful in gene mapping because:
1. | They have endoreduplication chromosomes |
2. | These are fused |
3. | These are easy to stain |
4. | These are much longer in size |
Identify the correct statements regarding linked genes:
I. | are located near each other on the same chromosome. |
II. | violate the law of independent assortment. |
III. | segregate together during meiosis. |
1. | I & II only | 2. | I & III only |
3. | II & III only | 4. | I, II & III |
The pedigree shown below cannot be:
I. | Autosomal dominant disorder |
II. | Autosomal recessive disorder |
III. | Sex-linked dominant disorder |
IV. | Sex-linked recessive disorder |
V. | Holandric disorder |
1. | I, II, and III only | 2. | I, II, III, and V only |
3. | I, III, IV, and V only | 4. | I, II, III, IV and V |
Assuming independent assortment, the ratio of progeny with the genotypes AaBb : Aabb : aaBb : aabb from a dihybrid cross AabB X AaBb will respectively be:
1. | 4 : 3 : 2 : 1 | 2. | 4 : 4 : 2 : 1 |
3. | 4 : 2 : 2 : 1 | 4. | 4 : 2 : 1 : 1 |
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X- linked recessive. What proportion of their sons would be color-blind and of normal height?
1. | All | 2. | None |
3. | Half | 4. | One out of four |