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Scientists Map Neanderthal Genome
goran72 writes "In a development which could reveal the links between modern humans and their prehistoric cousins, scientists said they have mapped a first draft of the Neanderthal genome. Researchers used DNA fragments extracted from three Croatian fossils to map out more than 60 percent of the entire Neanderthal genome by sequencing three billion bases of DNA."
You should not be in the zoo. No, you should not be in the zoo. With all the things that you can do, the circus is the place for you.
On a serious note, there are a few scientific issues at stake here.
First let me explain this "positive selection" stuff from the article. When a mutation within a coding region of a gene takes place, it can either be a silent mutation (no change in the resulting proteins) due to the redundancy of the genetic code, or it can change the amino acid sequence of the protein and thereby possibly its function.
Now, mutations happen at random. But depending on what kind of an effect the changes have, they might be wiped out by natural selection. For example, mutations in the "core system", the "kernel" of any living cell -- replication machinery usually are wiped out, because the machinery is so finely tuned that most mutations seriously screw it up. If the changes are largely neutral, the ratio of the mutations that have an effect divided by mutations that are silent (so called dN/dS ratio) is roughly equal to what we would expect based on random model, and we speak of neutral evolution.
On the other hand, environmental pressure, change of times, parasite pressure or many other things can lead to an accelerated rate of evolution -- measured by the fraction nonsynonymous mutations / silent mutations. Thus, one can detect whether a species, gene or genome was subjected to a specific pressure. And if we look at the whole genome, we can tell a lot about what this pressure was. And of course, it works both ways -- we can tell a lot about what the pressure was that shaped us, humans.
* of course, learn more about neanderthals -- who were they, did they mix with humans (current analyses say no, but who knows what one can find in the whole genome). Were they human at all? Did they really talk? What kind of culture did they have?
* by learning about divergence between neanderthals and homo sapiens, answer the fundamental questions of biology -- who are we? what makes us different from animals? What made us spread and neanderthals disappear?
* analysis of genome instead of single genes takes the whole thing up one level.
* tracing back evolution (in general, it is not only about human evolution) -- not by comparing sequences of organisms that live nowadays, but really going back in time. Among others, this will let us test the tools that we routinely use for phylogenetic analysis (that is, tracing back the evolution).
Regards,
j. (who currently works on genome evolution in bacteria)
I kinda doubt it. Neanderthals went extinct so long ago, that I doubt that any stories or myths from that age would have survived as long.
We're talking long before humanity invented writing, so the only way it could have survived is if the shaman of a tribe taught his apprentice about it, and so on. For some tens of thousands of years straight. I'd think that's rather unlikely. They had more pressing concerns in the here and now than "those guys our ancestors lived in the same cave with."
Basically, how many folk stories do we have about woolly mammoths? Why would Neanderthals be remembered more?
A polar bear is a cartesian bear after a coordinate transform.
The serious answer is that they believe that the bone fragments are either human in origin or mocked up from bones of existing apes.
There is no Neanderthal species for ID proponents. The answer is either they are human or they never really existed and the evolutionists are involved in a vast conspiracy to validate their own beliefs by creating these "pre-human" humanoids.
Yes, it is fascinating, but you have to take into account that FOXP2 is a transcription factor that acts when "collaborating" (dimerising) with other transcription factors (or itself) to regulate a whole range of different genes, which in turn can affect a whole range of physical (phenotypical) features (like speech development). True, people who have a mutation in FOXP2 are normal, but are not able to coordinate the movements required to speak, and this is a quite specific effect. But FOXP2 has definitely other "applications" as well - it is required for correct brain development in general, for example.
This makes any changes (or lack of them) very hard to trace back to specific effects. The fact that neanderthals had the same "version" (allele) of this gene might be an indicator, but then -- it might just be a coincidence. Chimps are just two mutations away.
What complicates the picture even more is the fact that not only the actual sequence of the protein matters -- also the regulatory sites around it (where other transciption factors bind and promote / inhibit the activation of FOXP2). And these tend to be variable even when they work very similarily.
j.