Monday, June 15, 2015

Homo heidelbergensis .... the time was wrong

Homo heidelbergensis
Photograph by Javier Trueba, Madrid Scientific Films

(Editor's Note: This brief article was originally published by the Cleveland Museum of Natural History. It offers, I believe, further support for my May 3, 2015, post, "There never will be just one." Whatever .... I find this concept fascinating and, maybe, you will, too .... and, think of this as a continuation of a prelude, but not really a tease.)

CLEVELAND, OHIO — Fossils of the upper and lower jaw of a new early human ancestor were discovered in the Woranso-Mille area of the Afar region of Ethiopia by an international team of scientists led by Yohannes Haile-Selassie of the Cleveland Museum of Natural History. The Australopithecus deyiremeda fossils are 3.3 to 3.5 million years old, overlapping with Australopithecus afarensis, who lived from 2.9 to 3.8 million years ago. Australopithecus deyiremeda differs from the famous "Lucy" fossils in the size and shape of its thick-enameled teeth and its robust lower jaws, suggesting that the two closely related species had different diets.

"Current fossil evidence from the Woranso-Mille study area clearly shows that there were at least two, if not three, early human species living at the same time and in close geographic proximity," Haile-Salassie said in a press release. The name of the new species, deyiremeda, (day-ihreme-dah) means "close relative" in the language spoken by the Afar people. To read about more recent evolutionary history, go to "Our Tangled Ancestry."

Our Tangled Ancestry
By Zach Zorich

When scientists attempt to draw the evolutionary family tree of the human race, they would like to be able to use straight lines to show the relationships between hominin groups: one species leads to another, and so on. But this isn't always possible. Three recent studies of ancient DNA have uncovered unique genetic markers in unexpected places, showing that our ancestors got around and interbred more than anyone had previously thought. The result is a convoluted set of relationships among early humans where once there was a simpler family tree.

The story of this new work begins in northern Spain. There, a group of Spanish researchers at the site of Sima de los Huesos teamed up with geneticists from the Max Planck Institute for Evolutionary Anthropology to examine the oldest known hominin DNA sample, which comes from a 400,000-year-old Homo heidelbergensis thigh bone. They sequenced the bone's mitochondrial DNA (mtDNA), which is passed from mother to child. "What we were expecting to see was Neanderthal mitochondrial DNA," says Matthias Meyer of the Max Planck Institute, as Neanderthals would later occupy that part of Europe and might be expected to carry genetic material from the previous inhabitants. Surprisingly, the mtDNA is instead more closely related to that of a hominin who lived more than 50,000 years ago in Siberia's Denisova Cave than it is to that of Neanderthals. The Denisovans were related to, but genetically distinct from, Neanderthals.

According to Meyer, the Sima de los Huesos sample is old enough that it could represent an ancestor to both Denisovans and Neanderthals. However, it is also possible that Homo heidelbergensis is not ancestral to either group, but later interbred with the Denisovan lineage. Studies of nuclear DNA, which contains genetic information from both parents, will be needed to clarify the relationship, Meyer believes.

Max Planck Institute scientists also recently sequenced the genome of a second individual who lived at Denisova more than 50,000 years ago. They discovered that the individual was actually a Neanderthal, not a Denisovan. It is the most complete Neanderthal genome yet recovered, and it has given geneticists a novel point of comparison among various human lineages. The new analysis shows that occasional interbreeding between Neanderthals, Denisovans, and Homo sapiens probably took place in more than one time and place, and that the Denisovans also interbred with an unknown archaic hominin group -- possibly Homo heidelbergensis.

According to another new study with surprising results, a small percentage of the Denisovans' unique DNA still lives on in the indigenous people of Australia, New Guinea, and the eastern islands of Indonesia -- all places that are separated from the Asian mainland by strong ocean currents that form a migratory barrier called the Wallace Line. Based on the lack of Denisovan DNA markers in ancient and modern populations on the Asian side of the line, and their relative abundance on the other, Alan Cooper of the University of Adelaide and Christopher Stringer of London's Natural History Museum believe that Denisovans may have boated to locations across the Wallace Line and interbred with the Homo sapiens already living there.

While these studies paint a complex picture of our genetic past, Meyer believes the relationships between ancient humans will become clear as methods for recovering ancient DNA improve. "In the next year or two," he says, "we will have a much, much higher-resolution picture of human migrations out of Africa and within Eurasia."

(Closing Note: So, say I once again, we are not a singular, straight line species, but a variety of species which have intermingled and may have as many branches as there are stars in the sky and have indeterminate genetic influences forming us, guiding us, controlling us. There are innate traits which explain good and evil, among other differences. Science will establish it. Perhaps, the assorted twain shall meet, but do not count on it happening anytime soon and, probably, not without "genetic engineering." Finally, to place a trace of my own genetic markers in this post, I will add this observation: Theodore "Teddy" Roosevelt was reckless but right; Barack Obama is a narcissistic idiot. Make of that remark what you will. And, for a bit of music to accompany the thoughts expressed, I will include a pair of songs from one of my favorite Twenty-first Century bands, The Killers. Make of the music what you will ....)




6 comments:

ANITA said...

Love that skeleton !!!

I dont know much about the others things you write!Sorry!!

Best wishes for the day!

Anita

Noushka said...

Hi,
Thanks from dropping by on my blog :)
scientists will always come up with with pieces of evidence about our ancestry and our genealogical tree, but I believe it will take still take ages before we understand the whole truth!!
The general public and most scientists do not knows what went on in the last millions of years on this planet and the incredible leap from humanoids to the humans we are today is a bit too amazing to have happened just by chance...
But this is only my personal feeling :)
All I know is that I know nothing!!
Take care, abrazos!!

Smareis said...

Olá Fram!

Uma imagem que mostra claramente como o ser humano termina. Apenas ossos. Uma obra maravilhosa criada e construída pela mão do CRIADOR.

Os cientistas sempre procurando comprovar, descobrir algo que talvez eles jamais consigam, sobre a árvore genealógica, antepassados do ser humano. Evidencias de algo que talvez passe séculos e mais séculos e eles ainda vão estar à procura de fatos que comprove algo a respeito. Há coisas que só o DEUS pode ter acesso, e jamais o homem vai ter permissão para descobrir mesmo que passe a vida tentando. Penso, que a tantas coisas que os cientistas deveriam se empenhar em descobrir para ajudar a humanidade: Curas para tantas doenças que ainda não conseguiram desvendar.

Uma excelente postagem, muito bem construída.
Bom que voltou com suas postagens!

Os dois vídeos é excelente. Boa as músicas.

Ate breve com sorrisos!

Fram Actual said...

Well, I am just glad you decided to stop by and to say hello, Anita.

I think much of what I write is of little interest to most who pass through here, but you are among the few who take time to greet me and I appreciate that kindness.

It has been a pretty good day, thank you, Anita. I hope life is treating you well.

Fram Actual said...

It is as I mentioned, Noushka. Whenever you publish a new batch of photographs on your blog, I stop by and look at them and admire them, although I do not always leave a comment. I guess, actually, I rarely leave a comment.

I am especially in love with ducks and geese in the realm of wildlife, and I am especially happy when you post photographs of them.

I quite agree with everything you wrote here, and I am very skeptical that the exact pathway from hominin to Homo sapiens sapiens will ever be traced, much less the journey from life itself to the hominin stage. My primary point is that the pathway has been like a river with many tributaries, and that genetic variations have evolved from countless differing sources to the degree where there really is no such thing as homo sapiens sapiens -- there are at least a few subspecies of them (which is to say, of us) which are almost indistinguishable from one another.

Put most simply, I think it is our differences which make us human, not our similarities.

Anyway, like you, I do have a feeling that there is more to this journey than random chance.

Thank you, Noushka, for your visit and your comment.

Fram Actual said...

My interests as a student and even later into life leaned more toward archaeology than anthropology, Smareis, but somewhere along the line as science began to probe more deeply into areas like genetics and DNA, my perspective of our existence became more and more curious about what was happening on earth before the dawn of known history. Anthropology began to gain a greater role. That is one origin of posts such as this one.

Another point of beginning was searching within mythology and religion for an explanation of widely disparate factors of the human experience, such as why there seems to be innate good and innate evil among men. What is the reason for such extremes?

The answer, to me, must be that there are countless genetic trails of development from even before the existence of hominins which leads me to believe some men are genetically disposed to be evil while others are not. Even more basic and less dramatic is the fact that some people are disposed to react one way when they see the color red, for instance .... or blue or yellow .... and other people react other ways when they see them. Why is this? Genetic differences, I think.

Anyway .... this brief explanation has not been written/explained well/clearly, but I hope you get my drift.

I agree with you that it probably would be more beneficial for mankind to spend more money, time and resources finding cures for diseases than on trying to unravel what has taken place on earth over billions of years. Humankind will never have a clear vision of this unless there is some manner of illumination which occurs in an afterlife, and I do think there is a chance for it. Much about life is random, in both an individual sense and a collective sense, but it seems reasonable to believe there must have been a match to light the fuse to create the explosion of life.

You have been absent so long that it has worried me, Smareis. I am glad you found your way back to visit me and to write a comment for me. Thank you. And, I hope you do not drift so far away for so long a time in the days ahead.

Something special ....