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Q. No.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 |
A dihybrid test cross leads to a frequency of recombinants of 50% in progeny. The most obvious conclusion will be:
| 1. | The two genes likely are located on different chromosomes. |
| 2. | All of the offspring have combinations of traits that match one of the two parents. |
| 3. | Abnormal meiosis has occurred. |
| 4. | Independent assortment is hindered. |
If a chiasma forms between the loci of genes A and B in 20 % of the tetrads of an individual of genotype AB/ab, the percentage of gametes expected to be Ab is:
| 1. | 40 | 2. | 20 |
| 3. | 10 | 4. | 5 |
What map unit (Centimorgan) is adopted in the construction of genetic maps?
| 1. | A unit of distance between genes on chromosomes, representing 50% cross-over. |
| 2. | A unit of distance between two expressed genes, representing 10% cross-over. |
| 3. | A unit of distance between two expressed genes, representing 100% cross-over. |
| 4. | A unit of distance between genes on chromosomes. representing 1% cross-over. |
The frequency of crossing over between any two linked genes will be:
| 1. | Higher if they are recessive |
| 2. | Dependent on how many alleles there are |
| 3. | Determined by their relative dominance |
| 4. | Proportional to the distance between |
Consider crossing over does not take place between chromosomes shown as:
(i) Chromosome 1: ABC/abc
(ii) Chromosome 2:Qr, qr.
Which of the following gametes will not be formed by this organism?
| 1. | ABCqr | 2. | abcqr |
| 3. | ABcqr | 4. | abcQr |
The recombination frequencies for four different linked genes of Drosophila are shown in the figure:
The order of the four genes will be:
| 1. | rb-cn-vg-b | 2. | vg-b-rb-cn |
| 3. | cn-rb-b-vg | 4. | b-rb-cn-vg |
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Q. No.
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