How our DNA differs from that of Denisovans, our extinct cousins

LA Times ^ | 9-1-12 | Rosie Mestel

[Pharmboy]

Scientists are beginning to analyze the DNA differences between modern humans and our extinct archaic relatives, the Denisovans. (National Human Genome Research Institute)

Genome of ancient Denisovans may help clarify human evolution

Scientists recently reported they had pieced together a high-quality sequence of an archaic human relative, the Denisovans.

Among other things, the researchers took a close look at the ways in which we differ from these people, who were named after the place where their traces were discovered: Denisova Cave in the Altai Mountains of Siberia....snip

It's "fascinating" to see the DNA changes that spread to most or all modern humans since our line split off from that of the Denisovans and the Neanderthals, said senior author Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. It's like taking a look at the last steps in human evolutionary history.

"The amazing thing to me is that [it is] not an astronomically long list," he said at a press conference on Wednesday. ...snip

Boring down even further, the researchers found 23 amino-acid changes that we have but Denisovans and monkeys and apes don't have. These might be especially likely to be important in making us who we are, Paabo said.

"It's quite interesting to me that eight have to do with brain function and brain development ... and some of them have to do with genes which, for example, can cause autism when the genes are mutated," he said.

And the autism-linked genes are interesting because a lot of what it takes to get by in human society, with all its politics and manipulation, has to do with being able to "read" the likely feelings of others, to get inside the head of another person.

[Lazamataz]

The whole evolutionary theory is turned upside down by the 2nd law of thermodynamics which basically states that as things get older they become corrupt and archaic and and tend to anarchy.

You mistate the Second Law of Thermodynamics. That's not what it says at all. The Second Law of Thermodynamics states that "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state."

It speaks only to energy, not to corruption, the state of being archaic (whatever THAT dedinition is), or a tendency towards anarchy.

It also speaks to a closed system, in which no energy is added. The sun prevents the Earth from being a closed system.

If you also include the sun in the system, over billions of years, yes, the sun will dissipate in energy and potential energy.

But the Second Law cannot be applied to evolution on Earth in any meaningful way. Nor should it.

[MIchaelTArchangel]

Denis O’Van? Didn’t he pitch for Cincinnati in the 1950s? I am sorry to learn of his passing.

[Pharmboy]

Covering a lot of areas—as you say—is not a problem; however, what I DO find a bit irksome is that after each time I respond to you with some data, you totally ignore it and throw something else out.

[Pharmboy]

Well, Laz, I guess you paid excellent attention in physics class. Let me guess--your physics teacher did not look anything like this:

[Lazamataz]

No, actually, my physics teacher looked a lot like this:

Of course, if he'd have asked, I'd have hit it.

[SunkenCiv]

GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach	join list or digest view topics view or post blog bookmark post a topic subscribe
Thanks Pharmboy. Apropos of nothing, trolls and fruitbats are self-identifying. To all -- please ping me to other topics which are appropriate for the GGG list.

[SunkenCiv]

• Asperger's Man -- The Search for Multi-Regional Human Speciation

[SunkenCiv]

Old as hell, but not extinct.

[SunkenCiv]

If we don’t have one species changing into another, we still have evolution, because that’s merely change. The change is a consequence of small replication errors, i.e. mutations, during mitosis and other cellular activity.

I’m not my grandfather (or my grandmother), and that’s the consequence of dropping half of the chromosomes for just two generations. And since there are 23 chromosome pairs, I’m not getting an even number from each of my grandparents (iow, it’s not exactly one quarter from each grandparent). Each of us has 64 great-great-great-great-grandparents, which means that, unless there’s been a cousin marriage along one of the lines, at least 18 of those 64 ancestors passed down zero chromosomes to us. They are still the ancestors, because they had to have lived and had offspring, but their genetic information has vanished from at least some of their descendants.

At the 5th-great generation — 128 of them — 82 have left zero to the current generation’s individual. In the next generation back, 210 left nothing. In short, there are (for most of us) 46 lines going back. As genetic sequencing becomes cheaper and quicker, and many, many more are sampled, common ancestry will be easier to figure out (even if no name can be put on it) and each of the 23 chromosome pairs will be grouped by common origin, and the number of groups will probably be in the high teens, at least.

[null and void]

Oh My Gawd!

[Ken H]

Well, Laz, I guess you paid excellent attention in physics class. Let me guess--your physics teacher did not look anything like this:

I'd have 'leapt on' it.

[Hiddigeigei]

Give it up! You can’t reason with faith. Faith, by definition, is the suspension of reason.

[SunkenCiv]

http://www.youtube.com/watch?v=qQTqKcojrVY

[Lazamataz]

Give it up! You can’t reason with faith. Faith, by definition, is the suspension of reason.

Perhaps. And I have faith in the presence and existance of God.

But just because I cannot reason with someone who abandons reason, I *still* can cause them to need to drop the citation of mathmatical and physical principles, when those principles simply do not apply.

[Pharmboy]

Yeah...the ones I had looked like that too, more or less...

[William Tell]

SunkenCiv said: "... at least 18 of those 64 ancestors passed down zero chromosomes to us. "

That is exactly how I was taught human genetics about forty years ago.

Have there been developments since then that describe a process whereby some information gets exchanged between the members of a pair of chromosomes before meiosis takes place? I think the process is perhaps not as simple as some of us were taught and that the math you describe, although correct for the simpler model we were taught, is not, in fact, what actually happens.

Perhaps there is a recently trained geneticist reading this thread who can clarify this.

[Condor51]

He is NOT extinct! He is a world class dart thrower!

{Thank you}

[SunkenCiv]

There’s a little bit, yeah. There’s nothing significant enough to alter the basic model to the extent as has been claimed somewhere around FR (another topic, perhaps a year ago), by some nimrod who claimed that the result was that *exactly* one quarter of our genes came from *each* grandparent. The basic math is good enough to get the basic understanding of what’s going on. Or course, given that the human genome data currently available indicates that everyone’s got almost exactly the same DNA (much of it “junk DNA”), none of this matters, eh? ;’)

[reasonisfaith]

Don’t overlook the fact that reason cannot justify itself on a metaphysical level.

[reasonisfaith]

My posts #11 and 16 do in fact respond to your post # 14.

Without morphological change, evolution has no meaning.