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Molecular Evidence for Evolution

Introduces molecular clocks as evidence of evolution.

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A Family Condition
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A Family Condition

What's The Use Of Spare Genes?

So you've heard of genes - not jeans, but genes. And you probably know they have something to do with how proteins are made, and how people work, internally that is. But did you ever wonder where genes originated? There are lots of different organisms, and they all have different numbers of genes. Humans are estimated to have around 23,000; roundworms are estimated to have 20,000; and the mighty water flea (Daphnia) around 31,000 (take note these are estimates and likely to change). So why don't all organisms have the same number of genes if we are all related? How can organisms get more genes? Well, this isn't a question that is easily answered, but researchers are working on it and making progress. One area they are focusing on is gene duplication. This area is particularly intriguing because it seems that similar animals have similar duplications.

Extension Investigation

Use the resources below to answer the following questions:

  1. How do organisms pick up "extra" copies of genes?
  2. How can having extra genes be an advantage to organisms?
  3. When have researchers estimated that primates picked up extra genes? Why is this timing important to determining how these duplications affected relationships between primates?

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