Thursday, July 15, 2004
You're the Great Pumpkin Charlie Brown
I think it's kinda funny how the NRO says "the BBC reports" like it's breaking news or something. That article is from five years ago and even then it wasn't new news. But yeah, it's good to remind people of the unity and diversity of all life.
In regards to the 75% number. They give no explanation where this number came from. Most likely it came from DNA melting experimetns which have been done for the past 40 years or so. To make a long story short, the more similar the sequences from two species, the higher the temperature that is required to seperate (melt) them. e.g. This is where the 99.9% figure for chimpanzees comes from as well. Although, the chimp genome is about to go online soon as well.
However, with the true sequences, we can now come up with better methods of comparision, but the whole area of sequence comparision is a non-trivial subject.
Another thing, I'd wager that the two most disparate organisms on Earth would still share at least 33-40% similarity in their DNA.
In regards to the 75% number. They give no explanation where this number came from. Most likely it came from DNA melting experimetns which have been done for the past 40 years or so. To make a long story short, the more similar the sequences from two species, the higher the temperature that is required to seperate (melt) them. e.g. This is where the 99.9% figure for chimpanzees comes from as well. Although, the chimp genome is about to go online soon as well.
However, with the true sequences, we can now come up with better methods of comparision, but the whole area of sequence comparision is a non-trivial subject.
Another thing, I'd wager that the two most disparate organisms on Earth would still share at least 33-40% similarity in their DNA.
The high correlation of genetic "stuff" between species that otherwise appear quite disimilar also provides a strong supporting argument for evolution.
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