Ancient DNA reveals secrets of human history

Nature News ^ | 9 August 2011 | Ewen Callaway

[neverdem]

Modern humans may have picked up key genes from extinct relatives.

For a field that relies on fossils that have lain undisturbed for tens of thousands of years, ancient human genomics is moving at breakneck speed. Barely a year after the publication of the genomes of Neanderthals1 and of an extinct human population from Siberia2, scientists are racing to apply the work to answer questions about human evolution and history that would have been unfathomable just a few years ago.

The past months have seen a swathe of discoveries, from details about when Neanderthals and humans interbred, to the important disease-fighting genes that humans now have as a result of those trysts.

Click for larger imageNeanderthals were large-bodied hunter-gatherers, named after the German valley where their bones were first discovered, who roamed Europe and parts of Asia from 400,000 years ago until about 30,000 years ago. The Neanderthal genome — shepherded by Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany — indicates that their evolutionary story began to split from the lineage of modern humans less than half a million years ago, when their common ancestor lived in Africa (see 'The human strain'). In December last year, Pääbo's team released the genetic blueprint of another population of ancient humans — unlike ourselves or the Neanderthals — that was based on DNA recovered from a 30,000–50,000-year-old finger bone found in a cave in Denisova in southern...

--snip--

Since then, scientists have fleshed out the details of one of the biggest surprises from the Neanderthal genome: humans living outside Africa owe up to 4% of their DNA to Neanderthals. One explanation might be that humans migrating out of Africa mated with Neanderthals, probably resident in the Middle East, before their offspring fanned out across Europe and Asia...

[muawiyah]

Self portrait I take 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
Note: this topic is from . Thanks Pharmboy and neverdem for the pings. The Neandertal Enigma by James Shreeve in local libraries Frayer's own reading of the record reveals a number of overlooked traits that clearly and specifically link the Neandertals to the Cro-Magnons. One such trait is the shape of the opening of the nerve canal in the lower jaw, a spot where dentists often give a pain-blocking injection. In many Neandertal, the upper portion of the opening is covered by a broad bony ridge, a curious feature also carried by a significant number of Cro-Magnons. But none of the alleged 'ancestors of us all' fossils from Africa have it, and it is extremely rare in modern people outside Europe." [pp 126-127] The Scars of Evolution: What Our Bodies Tell Us About Human Origins by Elaine Morgan "The most remarkable aspect of Todaro's discovery emerged when he examined Homo Sapiens for the 'baboon marker'. It was not there... Todaro drew one firm conclusion. 'The ancestors of man did not develop in a geographical area where they would have been in contact with the baboon. I would argue that the data we are presenting imply a non-African origin of man millions of years ago.'" To all -- please ping me to other topics which are appropriate for the GGG list.

[neverdem]

Epigenetics is also not “outside of the double helix” it involves methylation of the double helix molecule.

Histone Acetylation, DNA Methylation and Epigenetics

There may be another method used to affect gene expression that I'm forgetting.

[allmendream]

Promoter sequences and transcription factors for two. Histones are what are attracted to the methylated DNA.

My point is that controlling the expression of what is inherited is not some separate outside thing to what is inherited, neither is methylation outside the DNA double helix - but inside where the bases pair bond to keep the two phosphate backbones together.

Methylated DNA is more attracted to deAcetylated Histones - the two are listed together for a reason.

To activate a gene inactivated through epigenetic, the signal activated proteins Acetylate the Histones bound to DNA before they can get to the methylated DNA, that can then be demethylated and expressed - until the signal to methylate it and deacetylate histones is given and the DNA is wrapped up again - unreadable because it is unreachable by RNA polymerase that might - with the correct transcription factors - express its signal.

The mutation in some human populations that ensures lactose tolerance into adulthood is a mutation in the DNA element to signal to wrap up the lactose gene after weaning that is present in all mammals.

There is - within DNA - the proper sequences to react to changes and pass on reproductive cells with particular DNA configurations of being ‘open’ or ‘closed’ that we call epigenetic. It is DNA that is coding for and reacting with the signals it receives to adopt the proper epigenetic configuration of ‘open’ and ‘closed’ DNA.

[Ethan Clive Osgoode]

And, now is about the time when some liberal academic is gonna tell me I’m descended from a monkey, or an AFRICAN “Lucy”, huh?

Well, evolutionists have had a long history of fantasies about neanderthals and supposed "ape-men". For example, this is what evolutionists used to say about neanderthals...

…earlier than… 10,000 years ago, human beings wandered over the greater part of Europe… They were below the cultural level of the Australian native. Their beetling eye-ridges, retreating foreheads, heavy chinless jaws, and protruding teeth, are quite in accord with their stone implements, and betray a very low level of mental culture. They had no agriculture, no bows and arrows, no tamed cattle, no pottery, no woven texture, and probably — as we shall see — no clothing and no articulate speech… From the earliest remains found, these men are given the name of the Neanderthal race.

The general physical and mental character of this race is now firmly established… they belonged to an extraordinarily primitive type of man. All controversy as to the normal human character is now over, and the skeleton is admitted to be that of a man of the early part of the Old Stone Age. The thigh-bones were very heavy and much curved, and they and the other bones indicated very powerful muscles and a very moderate height. The man stood about 5 feet 3 inches, his legs slightly curved, and his limbs and chest of great power. His large teeth bulged outward, and there was little chin. Two thick bony ridges stood out far over his eyes, and his forehead was extremely low. The skull might contain 1,220 cubic centimetres of brain matter, which is much the same as that of an Australian native. Some writers have represented that this is a fair capacity for a man of 5 feet 3 inches, and greater than that of many Veddahs and Andamanese. The latter, however, have very slight frames to control, unlike the Neanderthal man. As Huxley said, the skull was “the most brutal of all human skulls” at the time it was discovered.

...The thigh-bones were thick and curved, and they and the other bones indicated very powerful muscles. We had the same suggestion of a squat, powerful, stunted savage, with brain and facial features going back toward those of the ape.

[ThanhPhero]

It is all a matter of definition and scientists disagree. For some if animals can interbreed naturally and produce fertile offspring then there is there only one species. For others any distinct population is a separate species and it is terrible when they interbreed and mess up the charts.

[allmendream]

I don't think any respected taxonomists insists that Tigers and Lions are the same species.

Tigers and Lions can and do produce fertile offspring.

Reality doesn't conform as well as some would like to neat little boxes. Science likes to put things into neat little boxes - but putting things in boxes is not itself science.

[chesley]

It does sort of depend on what the meaning of “species” is, doesn’t it.

What do you call two or more groups of animals, not subspecies of the same species, who can freely mate and produce fertile offspring? I’m assuming that they would all be within the same genus, but suppose they were also other similar species within the genus that could NOT produce fertile offspring?

Is there such a biological word? It’s been a long time since high school.

[allmendream]

What do you call two or more groups of animals that are not subspecies of the same species, but who can mate and produce fertile offspring?

Closely related.

For example: Tigers and Lions are closely related members of the feline ‘family’ that can produce fertile offspring.

Another example: Coyotes and Wolves are closely related members of the canine ‘family’ that can produce fertile offspring.

Words are, and always will be, imprecise reflections of reality. They are not themselves real, nor do they dictate reality.

[chesley]

Words are, and always will be, imprecise reflections of reality. They are not themselves real, nor do they dictate reality.

Exactly!

[SunkenCiv]