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Sister chromosome exchanges are recombination events that occur between homologous chromosomes and are often the result of exposure of the cell to DNA damaging agents.
Cross over, or recombination, is the exchange of chromosome segments between non sister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity.
It seems that you have missed the necessary options for this question, but anyway here is the answer. Glaucoma has been one of the leading causes of blindness and a common form has been linked to three genes and more that 20 genetic loci. So the statement that best describes glaucoma is that, <span>a polygenic trait that is influenced by the number of alleles present. Hope this answer helps.</span>
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