Chapter 5 Part 4: Principle of Inheritance and Variations

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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p>Offsprings</p>
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<th style="text-align:center">$\sigma^{\top}$</th>
<th style="text-align:center">TR</th>
<th style="text-align:center">Tr</th>
<th style="text-align:center">tR</th>
<th style="text-align:center">tr</th>
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<td style="text-align:center">tr</td>
<td style="text-align:center">TtRr <br> (tall and red)</td>
<td style="text-align:center">Ttrr <br> (tall and white)</td>
<td style="text-align:center">ttRr <br> (dwarf and red)</td>
<td style="text-align:center">(dwarf and white)</td>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p><strong>Ans.</strong> Colourblindness is a X-inked sex inheritance.</p>
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<li>For becoming colourblind, the female must have the allele for it in both her $\mathrm{X}$-chromosomes and if only one $\mathrm{X}$-chromosome of female possess allele for colour blind character she becomes the carrier for this characteristics But males develop colourblindness when their sole $\mathrm{X}$ - chromosome has the allele for it.</li>
<li>Thus males are more prone to colour blindness while females are carriers.</li>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<li><strong>Applications of Recombination</strong></li>
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<p>(i) It is a means of introducing new combinations of genes and hence new traits.</p>
<p>(ii) It increases variability which is useful for natural selection and under changed environment.</p>
<p>(iii) Since, the frequency of crossing over depends upon the distance between the two genes, the phenomenon is used for preparing linkage chromosome maps.</p>
<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p><strong>Ans.</strong> Incomplete dominance is a phenomenon where two contrasting alleles are present together but neither of the alleles is dominant over other and the phenotype formed is intermediate of the two alleles. e.g., the kind of inheritance in the dog flower (Snapdragon or Antirrhinum species) in which the intermediate trait is expressed in $\mathrm{F}_{1}$-generation.</p>
<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p>(ii) <strong>Blood group showing co-dominance</strong></p>
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<th style="text-align:left">Genotype</th>
<th style="text-align:center">Surface Antigen</th>
<th style="text-align:center">Blood Group</th>
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<td style="text-align:left">$\mathrm{I}^{\mathrm{A} i}$ (dominance)</td>
<td style="text-align:center">$\mathrm{A}$</td>
<td style="text-align:center">$\mathrm{A}$</td>
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<td style="text-align:left">$\mathrm{I}^{\mathrm{A}}{ }^{\mathrm{A}}$</td>
<td style="text-align:center">$\mathrm{A}$</td>
<td style="text-align:center">$\mathrm{A}$</td>
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<td style="text-align:left">$\mathrm{I}^{\mathrm{B} i}$ (dominance)</td>
<td style="text-align:center">$\mathrm{B}$</td>
<td style="text-align:center">$\mathrm{B}$</td>
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<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<th style="text-align:left">Genotype</th>
<th style="text-align:center">Surface Antigen</th>
<th style="text-align:center">Blood Group</th>
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<td style="text-align:left">$\mathrm{I}^{\mathrm{B}} \mathrm{I}^{\mathrm{B}}$</td>
<td style="text-align:center">$\mathrm{B}$</td>
<td style="text-align:center">$\mathrm{B}$</td>
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<td style="text-align:left">$\mathrm{I}^{\mathrm{A}} \mathrm{I}^{\mathrm{B}}$ (co-dominance)</td>
<td style="text-align:center">$\mathrm{AB}$</td>
<td style="text-align:center">$\mathrm{AB}$</td>
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<td style="text-align:left">$\mathrm{ii}$</td>
<td style="text-align:center">-</td>
<td style="text-align:center">$\mathrm{O}$</td>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p><strong>Ans.</strong> Sickle-cell anaemia is an autosomal recessive disease caused by haemoglobins an oxygen carrying protein in blood cells.</p>
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<li>Despite the disease’s lethal symptoms, it protects the carrier from malaria.</li>
<li>Its allele are most common in the people of African descent (about 7 % people of African descent carry an allele) and some other are as where malaria in prevalent.</li>
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<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ <span style="color:blue">Short answer type questions</span> $\rightarrow$ Long answer type questions
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<p><strong>Ans.</strong> Aneuploidy is a phenomenon which occurs due to non-disjunction, resulting in gain or loss of one or more chromosomes during meiosis.</p>
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<li>Aneuploidy is different from polyploidy.</li>
<li>Polyploidy is a phenomenon in which the organisms contain more than two monoploid value or basic sets of chromosomes.</li>
<li>i.e., $-3 n$, 4netc.</li>
<li>Example of such organisms are certain fish and salamanders and is commonly found in plants like grapes, banana.</li>
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<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ Short answer type questions $\rightarrow$ <span style="color:blue">Long answer type questions</span>
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<Success><font size="5"><b>Principle of Inheritance and Variations</b></font></Success>
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<h4 id="primarylong-answer-type-questionsprimary-23"><Primary>Long Answer Type Questions</Primary></h4>
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<p><strong>Chromosomal Abnormalities</strong></p>
<p><strong>(a)</strong> Down’s syndrome is an autosomal disorder that is caused by the trisomy of chromosome 21.</p>
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<li>The individual is short statured with round head, open mouth, protruding tongue, short neck, slanting eyes, and broad short hands.</li>
<li>The individual also shows retarded mental and physical growth,under developed gonads and genitats, etc.</li>
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<p><Success>Ans. to be continued</Success></p>
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Multiple choice questions (MCQs) $\rightarrow$ Very short answer type questions $\rightarrow$ Short answer type questions $\rightarrow$ <span style="color:blue">Long answer type questions</span>
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