Inheritance & Variation
Crossing-overCrossing over, or recombination, is the exchange of chromosome segments between nonsister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity.
What Causes MutationsAcquired mutations occur at some time during a persons life and are present only in certain cells, not in every cell in the body. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division.
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Independent AssortmentThe chromosomes are pulled to opposite poles of the cell by spindle fibers However which member of each chromosome pair gets pulled to which pole is random.
Types of MutationsThe types of mutations include : Missense mutation. This type of mutation is a change in one DNA base pair that results in the substitution of one amino acid for another in the protein made by a gene.
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