Q. No.ABO blood groups in humans are controlled by the gene I. It has three alleles – IA IB and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?
1. Three
2. One
3. Four
4. Two
Select the correct statement from the ones given below with respect to dihybrid cross:
| 1. | Tightly linked genes on the same chromosome show higher recombinations |
| 2. | Genes far apart, on the same chromosome, show very few recombinations |
| 3. | Genes loosely linked, on the same chromosome, show similar recombinations as the tightly linked ones |
| 4. | Tightly linked genes on the same chromosome show very few recombinations |
Which one of the following symbols and its representation, used in the human pedigree analysis is correct?
| 1. |  = Mating between relatives |
| 2. |  = Unaffected male |
| 3. |  = Unaffected female |
| 4. |  = male affected |
Sickle cell anaemia is:
| 1. | an autosomal linked dominant trait |
| 2. | caused by substitution of valine by glutamic acid in the globin chain of haemoglobin |
| 3. | caused by a change in base pair of DNA |
| 4. | characterized by elongated sickle like RBCs with a nucleus |
Study the pedigree chart given below:
What does it show?
| 1. | Inheritance of a sex-linked inborn error of metabolism |
| 2. | Inheritance of a condition like phenylketonuria as an autosomal recessive trait |
| 3. | The pedigree chart is wrong as this is not possible |
| 4. | Inheritance of a recessive sex-linked disease like haemophilia |
| 1. | Klinefelter's syndrome-44 autosomes + XXY |
| 2. | Colourblindness – Y-linked |
| 3. | Erythroblastosis foetalis-- X-linked |
| 4. | Down syndrome--44 autosomes + XO |
Inheritance of skin colour in humans is an example of:
1. chromosomal aberration
2. point mutation
3. polygenic inheritance
4. codominance
Two genes R and Y are located very close on the chromosomal linkage map of the maize plant. When RRYY and rryy genotypes are hybridized, then F2 segregation will show:
1. higher number of the recombinant types
2. segregation in the expected 9:3:3:1 ratio
3. segregation in a 3:1 ratio
4. higher number of the parental types
A common test to find the genotype of a hybrid is by:
1. crossing of one F2 progeny with a male parent
2. crossing of one F2 progeny with a female parent
3. studying the sexual behaviour of F1 progenies
4. crossing of one F1 progeny with a male parent
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