Of all the evidence for evolution, some of the most compelling and irrefutable are the endogenous retroviruses. These are viruses that have embedded their code into germ line cells (sperm and egg) and thus become inactive but pass along their genetic information by inheritance. They act as genetic fingerprints that can indicate how closely related two organisms are.
Think of an incident of plagiarism; one author accuses another of plagiarizing his work due to similarities between the two. Is it an open and shut case? Not necessarily; it could be that the two just arrived at the same idea at the same time. However, one piece of evidence that would prove plagiarism is shared typos: if one author misspelled a word and the alleged plagiarist has the same error in his work, it would be strong evidence that the accused party had copied the words of the other, mistakes and all.
This is similar to how endogenous retroviruses work. At some point in the distant past, an ancestor organism was infected by a virus which then attacked and embedded itself in the reproductive cells, and became inactive as a virus. It's code was then passed on to the offspring, which continued to pass this genetic "typo" on to all of its ancestors.
Humans share several of these ERVs in common with chimpanzees, in the same place on the genome, in the same order. We share less with gorillas as they are more distantly related. And less still with orangutans and Old World monkeys as they are even less distantly related.
Family trees of organisms are built using ERV data, and the trees match up with the data from the fossil record. This is incontrovertible evidence for common ancestry; humans and chimps share an ancestor about 6 million years ago, regardless of fossils found.
And other animals ERV family trees match up with the fossil record as well. These shared mistakes in the genome present some of the most spectacular evidence and confirmation for the theory of evolution.
Martin Kulp is a writer with many distinct interests. He owns several websites on a variety of topics, one of which is information about prostate cancer. See his article on prostate cancer treatment centers at http://prostaide.org/prostate-cancer-treatment-center-options.
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