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Genetic diversity, meiosis and adaptations Typeit
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is a method of cell division which produces non-identical daughter cells. One way that variation is introduced is during the independent segregation of homologous that line up along the equator of a cell. If the sister chromatids become tangled, they may also exchange sections in what is known as , which can lead to genetic recombination. Furthermore, maternal and paternal combine randomly during , which creates even more possibilities for different combinations of genes.
Random during DNA replication can result in a change in the base sequence on a chromosome. For example, if a single base is removed (a base ), the triplet code means that all downstream codons may have changed. If one base is changed for another, it is known as a base . However, because the genetic code is , this may not always result in a change in the sequence of the polypeptide.
If these changes result in a different version of a gene, the diversity of the population increases. This new version of the gene, called an , may be advantageous to an individual and confer greater reproductive success; therefore, natural selection may act to spread it throughout the population since it is more likely to be inherited in the next generation than a different version of the gene.
Selection that acts to move away from the current average is known as selection, whereas selection is favoured in an environment where the selection pressures have not changed. As a result of selection, organisms develop different adaptations to their environment, which may be anatomical, physiological or .