Domain: plosgenetics.org
Stories and comments across the archive that link to plosgenetics.org.
Comments · 6
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Interesting, need more sample photos
I fished around the links in the article, including http://www.plosgenetics.org/ar... and it looks fascinating. But we really need to see more samples. The one of the reporter is quite good, but let's see them do it again.
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Re:Idle speculation
Personally, I'm more partial to the theory that we *are* Neanderthals (hybrids) and that they didn't 'die out', but were simply bred away...
This is an outdated theory (I used to like it myself though). There is evidence of gene flow between H. s. sapiens and H. s. neanderthalensis, but not very much. Theories that modern humans simply outbred them and replaced them are viable, but not ones that propose that the two species interbred to form a new single hybrid.
Consider this recent article: http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002947
.A key quote: "Although mitochondrial DNA from multiple Neandertals has shown that Neandertals fall outside the range of modern human variation, low-levels of gene flow cannot be excluded." In other words we definitely are not them, but may (probably do) have some of their genes.
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Re:Problem
Oh for shit's sake people, am I the only person who can use Google? Is 2008 good enough for you, assface? At a certain point when evidence is presented it becomes rather weak-looking to keep asking for more without presenting any evidence disproving those things already presented.
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Re:Evolution? How about natural selection?
(canceling mods for this comment)
How are they not the same thing? Isn't evolution just random mutation + sexual/viral crossover + natural selection?
Depends on if you use big-E or little-e for Evolution(as in the theory about life after abiogenesis/panspermia) or evolution (generic change over time)
Unless you agree abiogenesis 'created' all the different proteins we have now, then mutation is how humans have *2 000 000 different proteins* (but only 20 000 genes compared to Archaea with +/- 500 protein encoding genes)
So, we are aware of what SNPs do to genes and also how gene duplicating can provide a chance for those to change proteins. Note the one of the simplest proteins in humans, human serum albumin, it has 585 amino acids and 50 or so variants. Of those, most do nothing regarding function, and I could find none providing benefits.
Now, the largest protein in humans, titin, has 34 350 amino acids and many variants. This gene is interesting in that its variants are the result mainly of deletions and give rise to different kinds of striated muscles. (Heart vs bicep) But also this protein is used in chromosome condensation and segregation in mitosis. So here is *one* gene in humans that is made into at least 8 protein isoforms (different proteins of similar function) and without it, *mitosis* wouldn't work correctly.
So here are a few questions for you. Where does abiogenesis end and Evolution begin? How many genes were produced in abiogenesis? (obviously approximations are acceptable) How does Evolution explain the different proteins after that? How about all the different protein families? How do 20 000 genes make 2 000 000 proteins? Relatedly, can you explain what enables life to know and skip introns while only using exons with both precision and accuracy of 1 bp, every time, in all instances when a protein is properly made? Now how did that mechanism arise? How is it conserved?
How I understand it, DNA is information. But not only raw information, but it also contains the instructions to copy itself accurately. Not only that, but it carries all its 'metadata' accurately and its programming instructions accurately. That is because there are *repair* mechanisms also in place, within the same DNA. These are like md5 hashes where if not legit, then Destroyed!! All this within the same 3 000 000 000 bp. Rather like a computer (loaded to the hilt with programs) that has a 3d printer attached that prints more computer/printer 'babies' that are already 'built' (in IT terms) That is all within the genome.
Surely all these unknown can/will be known, (I'm not arguing deus ex machina) my point is that there is a whole world more to the genome than random mutation seems to be able to explain. Unless it all happened in abiogenesis.
PS, Correct me if I'm wrong, but aren't horizontal gene transfer and genetic drift (what you called sexual crossover) methods to propagate already existing genes?
PPS What happens when you separate populations of a lizard species for '8 million years' and then bring them back together? This
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Re:Article asserts three things; none yet proven t
As far as I can tell, this story attempts to make three points:
1. Human genomes tend to cluster into three groups: african, eurasian, and east asian.
Let's not ignore the fact that they picked these three populations in advance (from the original article):
In the following discussion, we focus on SNPs with extreme pairwise FST between three HGDP populations: the Yoruba, French and Han Chinese.
They then show in Figure 3 that selecting SNP that have very different distribution between these three populations also show similar distributions between African, Europe, and East Asia. However, squinting at the plot (my favourite method of statistical analysis), it looks as if these frequency distrubutions could as well be clines, partly obscured by an over-sampling of Chinese populations...
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Re:Maps of human travel on earthThis story sparked my interest so I searched for a while on the internet to find some maps of what the world looked like back in the ages and where evidence of people has been found linked with DNA evidence of how people actually have moved.
I sadly came up with nothing... anyone who knows where to find anything like this? Just RTFM Figure 4. Summary of inferred history of the peopling of the world