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microbiology1 microbiology1
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11 years ago
What process in the first prophase of meiosis makes every gamete different?
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wrote...
11 years ago
Genetic variation happens in two parts. Prophase I and Metaphase I.

During Prophase I crossing over occurs.

During Metaphase I independent assortment occurs.

so crossing over is your answer.
wrote...
11 years ago
Crossing over, which means that homologous chromosome pairs randomly exchange genes for the same trait between them. It is a bit like shuffling the deck. This crossing over insures that while each gamete has 50% of the DNA of the parent organism, exactly which genes are present on the chromosomes of different gametes are always different. For example, let's say that a person has genes for type A blood but is heterozygous, meaning he or she also has a gene for type O blood. Let's also say that this person has a gene for brown hair and a gene for red hair. There are millions of different traits, but let's just work with two!
This person could produce a gamete with a blood type O gene and brown hair gene, a blood type O gene and a red hair gene, a blood type A gene and brown hair gene, or a type A gene and red hair gene. That's 4 different combination possibilities for the gametes using only 2 different traits. You can imagine the possibilities with a full compliment of gene pairs; it is nearly infinite, as are the possibilities from the other parent's gametes. This is why no two members of the same species are exactly alike, and it gets more different in higher organisms.
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