The genotype of a husband is IAIB and that of a wife is IAi. How many different genotypes and phenotypes are possible in their progeny?
1. 2 genotypes; 3 phenotypes
2. 3 genotypes; 4 phenotypes
3. 4 genotypes; 4 phenotypes
4. 4 genotypes; 3 phenotypes

Subtopic:  Polygenic Inheritance & Pleiotropy |
 85%
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Linked genes:
I: are located on heterologous chromosomes.
II: do not assort independently.
 
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
Subtopic:  Understanding Linkage |
 80%
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T. H. Morgan was the first geneticist to:
1. associate a specific gene with a specific chromosome
2. explain the correct nature of the unit of inheritance
3. associate a metabolic block with inborn errors of metabolism
4. propose that a gene is responsible for making a protein
Subtopic:  Chromosomal Basis of Inheritance: Introduction |
 63%
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The mechanism of sex determination:
I: is XX/XO male heterogamety in Grasshoppers
II: is ZZ/ZW female heterogamety in birds
 
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
Subtopic:  Sex Determination |
 93%
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Consider the given two statements:
Assertion (A): Human skin colour trait is spread over a gradient rather than having distinct alternate forms.
Reason (R): Human skin colour is a polygenic trait.
 
1. Both (A) and (R) are True but the (R) does not correctly explain the (A).
2. Both (A) and (R) are True and the (R) correctly explains the (A).
3. (A) is False but (R) is True.
4. (A) is True but (R) is False.
Subtopic:  Polygenic Inheritance & Pleiotropy |
 67%
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Both parents are carriers for an autosomal recessive trait. What proportion of their progeny are expected to be affected by this disorder?
1. 0
2. ¼
3. ½
4. ¾
Subtopic:  Pedigree Analysis: More Examples |
 68%
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Consider the given two statements:
Assertion (A): X-linked recessive disorders are always expressed in males.
Reason (R): Males have only one X chromosome.
 
1. Both (A) and (R) are True but the (R) does not correctly explain the (A).
2. Both (A) and (R) are True and the (R) correctly explains the (A).
3. (A) is False but (R) is True.
4. (A) is True but (R) is False.
Subtopic:  Pedigree Analysis: Problem Solving |
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Consider the given two statements:
Statement I: The two alleles of a gene pair are located on homologous sites on homologous chromosomes.
Statement II: The pairing and separation of a pair of chromosomes would lead to the segregation of a pair of factors they carried.
 
1. Statement I is correct; Statement II is correct
2. Statement I is correct; Statement II is incorrect
3. Statement I is incorrect; Statement II is incorrect
4. Statement I is incorrect; Statement II is correct
Subtopic:  Chromosomal Basis of Inheritance: Introduction |
 88%
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Identify the incorrectly matched pair:
1. de Vries, Correns and von Tschermak Independently rediscovered Mendel’s laws
2. Walter Sutton and Theodore Boveri Gave chromosomal theory of inheritance
3. Sturtevant Discovered the mechanism of sex determination in fruit flies
4. T. H. Morgan Demonstrated that genes are carried on chromosomes
Subtopic:  Chromosomal Basis of Inheritance: Introduction |
 83%
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Mendel published his work on inheritance of characters in 1865 but for several reasons, it remained unrecognised till 1900. These reasons included all the following except:
1. Communication was not easy in those days.
2. His concept of genes (or factors, in Mendel’s words) as stable and discrete units that controlled the expression of traits and, of the pair of alleles which did not ‘blend’ with each other, was not accepted by his contemporaries as an explanation for the apparently continuous variation seen in nature.
3. Mendel’s approach of using mathematics to explain biological phenomena was totally new and unacceptable to many of the biologists of his time.
4. Although Mendel’s provided correct physical proof for the existence of unit factors as discrete entities, his explanations could mot convince others.
Subtopic:  Chromosomal Basis of Inheritance: Introduction |
 77%
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