What do you think of the research that suggests my European ancestors, as well as Asians, have Neanderthal DNA? How much interbreeding does the study suggest happened, a little or a lot? I ask because looking at Neanderthal skeletons and a Homo Sapiens skeletons, it is clear that there are major differences, despite the things we have in common as cousin species.
I also ask because there are people that are using these studies to support their racial hatred against other peoples (namely people of African ethnicity.) I'm not a geneticist, but I've always believed that the Caucasoid, Mongoloid, and Negroid races (if there is even such a thing as races) are so close to each other that any differences are just simply outward appearance and culture. Please excuse me if I used outdated terminology to describe the races, I mean no disrespect if I did. I pulled the terminology out of a somewhat dated scientific book I have.
Can you shed some light into these studies and what it means for our ideas about our modern human species?
Yes is true that there is some interbreeding, but there are few neanderthal genes in the genome of contemporary humans. Also there are evidence of interbreeding with Denisovan but also only a few genes. Is possible that it was useful for the first humans coming out of africa, but for the most part we simply fought and won, and got all the other
Homo species extint. The differences between "races" are negligible, but can be useful for some congenital diseases in poblations.
Also a lot of characteristics are more complex than "that gene x for that" and "the gene y is the adiction gene". All that are mere correlations and most of them weak at best. All is too complicated, not simply reduced to the genes. Is more happening in there and is more excinting and mysterious than we thought.
The latest research suggests very little interbreeding, I am not an expert, but the last paper I read suggested that an estimated 1% of the DNA in Europeans and Asians is of Neanderthal origin. This difference however is not "fixed", but mostly shifts in allele frequency.
As for the other part of your question, there are very few differences in DNA between races (again, mostly shifts in gene frequencies), and those were not detected before mostly because we didn't have complete genomes, but now we do, including Neanderthal genomes, so we have more accurate comparisons.
Now, racial hatred, people will find all kinds of excuses to hate each other...
Yes there are some evidence of interbreeding (1-4%) and yes is not fixed.
I mean, if I live where it is cold so I make a behavior change (like wearing a coat) and I teach this to my kids who teach it to their kids and so on and even after 10 million generations, physically my descendant still needs a coat but the coat design has been perfected...that 's not evolution but still man has changed in order to survive.
Its other kind of evolution, is cultural, on the mental level. But like CabVet said in that time is almost sure that some changes in the genome had taken place.
Ever done any thought experiments on what you think extraterrestrial life might look like? What differences do you envision are possible? Do you think nucleic acids are a universal "information molecule", or that proteins are a necessary or ubiquitous component of life?
For the first question. Yes (not only me is a great topic of study in theoretical biology), and the characteristics I think it most have is: semi-permeable membrane (for the difference of inside-outside), some kind information molecule (or molecules), a catalytic molecule (or molecules), a sign system for stimulus and selfcontrol, some way to obtain energy to synthetize these molecules, capacity of self organizing and reproduction.
I think the differences can be in what molecules do retain the information and which system of codification.
For the third. I don´t think nucleic acids are necessarily the "universal" information molecule. It depends on the conditions of the planet. But they most be a kind of polymers that can be complementary and interact in some way that is possible for them to auto replicate (maybe indirectly with other intermediary molecules) and carry some information. For proteins the same, there are other catalytic molecules like RNA but are unstable, it depends on the planet I think.
