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| Crossing Over |
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| Genetic recombination crossing over is the mutual exchange of the corresponding parts of the adjacent paternal and maternal chromatids of the pachytene of meiosisI, producing new combinations of genes. The chromatids resulting from the interchange of segments are known as the cross over recombinants and the chromatids that remain intact are called non-crossover parental chromatids. |
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| fig. 19.10 Crossing Over |
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| A Single Crossing, B Reciprocal Double Crossing Over, C and D Complementary Double Crossing Over |
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| fig. 19.11 Diagram Showing Crossing Over |
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| It produces 50% parental and 50% recombinant chromatids |
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| a. It produces new individuals having new combinations of traits. |
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| b. Crossing over has helped in establishing the concept of linear arrangement of genes. |
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| c. The frequency of crossing over helps in the mapping of chromosomes. i.e., determining the location of the genes in the chromosomes. |
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| d. Selection of useful recombination by geneticists has brought about green revolution in our country. |
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