The pedigree shown below, most likely, exhibits the inheritance of a/an:

1. Autosomal recessive trait
2. Autosomal dominant trait
3. X linked recessive trait
4. X linked dominant trait

Subtopic:  Pedigree Analysis: Problem Solving |
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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 |
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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 |
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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 |
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Consider the given two statements:
Assertion:  X-linked recessive disorders are always expressed in males.
Reason:  Males have only one X chromosome.
 
1.  Both Assertion and Reason are true but the Reason does not correctly explain the Assertion.
2. Both Assertion and Reason are true and the Reason correctly explains the Assertion.
3. Assertion is false but Reason is true.
4. Assertion is true but Reason is false.
Subtopic:  Pedigree Analysis: Problem Solving |
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When preparing genetic map using recombination data, it is assumed that 1% of crossing over equals:
1. one map unit.
2. two map units.
3. five two map units.
4. ten map units.
Subtopic:  Recombination & Gene Mapping |
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If the strength of linkage between y and w is higher than w and m [y, w and m are three linked genes located on a chromosome]:
1.
the number of recombinants between y and w will be higher than the number of recombinants between w and m.
2.
the number of recombinants between y and w will be lower than the number of recombinants between w and m.
3.
the number of recombinants between y and w will be equal to the number of recombinants between w and m.
4.
no recombinants between y and w and between w and m will be formed as they are linked.
Subtopic:  Understanding Linkage |
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Consider the two statements:
Statement I:    The dominant phenotype can be produced only by an organism with a homozygous dominant genotype.
Statement II:    The results of a test cross indicate whether an individual with the dominant phenotype is heterozygous or homozygous dominant.
 
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:  Monohybrid Cross: Further Understanding |
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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 |
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Identify the incorrectly matched pair:
Organism  Mechanism of sex determination
1. Honey bees  Haplo-diploidy
2. Grasshoppers  XX-XO female heterogamety
3. Birds  ZZ-ZW female heterogamety
4. Fruit fly  Genic balance
Subtopic:  Sex Determination: Further Considerations |
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