The Origin of Sexual Reproduction Draft

The Origin of Sexual Reproduction Draft - Helen Wang...

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Helen Wang Biology 108 Seminar The Origin of Sexual Reproduction Draft Because sexual reproduction is less efficient than asexual reproduction, many have debated why sex has become so prevalent among life cycles. However, before this question can be answered, the origin of sexual reproduction must be discussed. The development of the giant genome was the primary step towards the evolution of sexual reproduction. Random DNA segments called mobile elements were inserted into eukaryote genomes, increasing the size of genomes. Early eukaryotes reproduced by duplicating their giant haploid genomes and then dividing them (mitosis). However, diploid cells began to arise due to the failure of the division of two haploid cells or due to the fusion of two haploid cells. Large diploid genomes raised the risk of copying mistakes when eukaryotes copied their DNA because a chromosome could recombine (swap genes) with a nonhomologous chromosome and it would not receive the same genes back. To reduce this risk, homologous chromosomes tightly bound together before cell division so that
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The Origin of Sexual Reproduction Draft - Helen Wang...

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