...
EgyptSearch Forums Post New Topic  New Poll  Post A Reply
my profile | directory login | register | search | faq | forum home

  next oldest topic   next newest topic
» EgyptSearch Forums » Egyptology » Xyyman is right about Neanderthals

 - UBBFriend: Email this page to someone!    
Author Topic: Xyyman is right about Neanderthals
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
I'm noticing that if you just go by 23andme Neanderthal variants are not governed totally by the percent of SSA DNA. A person can be 98% SSA and have 50 variants while another can be 79% and have 20 variants. This is consistent. It appears that the Neanderthal signature doesn't show in Africans like it does with everyone else. It's African diversity. Less percentage of Neanderthal marbles.

Shouldn't the variants be be zero for people who are 98% SSA? And why is it that everyone regardless of OoA direction/path have more Neanderthal than Africans? Shouldn't there be isolated exceptions? Not if its about diversity instead of admixture.

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
Frankly Kemet
Banned
Member # 22882

Rate Member
Icon 1 posted      Profile for Frankly Kemet         Edit/Delete Post   Reply With Quote 
I thought Neanderthal arose out of Homo erectus of OoA?
Posts: 115 | From: NYC | Registered: Feb 2018  |  IP: Logged | Report this post to a Moderator
Ish Geber
Member
Member # 18264

Member Rated:
4
Icon 1 posted      Profile for Ish Geber     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Frankly Kemet:
I thought Neanderthal arose out of Homo erectus of OoA?

Do you have studies done on the Homo Erectus?
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010  |  IP: Logged | Report this post to a Moderator
xyyman
Member
Member # 13597

Rate Member
Icon 1 posted      Profile for xyyman   Author's Homepage         Edit/Delete Post   Reply With Quote 
@ Ish. This guy is a flamer. lol! SMH

quote:
Originally posted by Ish Gebor:
quote:
Originally posted by Frankly Kemet:
I thought Neanderthal arose out of Homo erectus of OoA?

Do you have studies done on the Homo Erectus?


--------------------
Without data you are just another person with an opinion - Deming

Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Doug M:
quote:
Biologists find clues to a 'ghost' species of ancient human in Africa and say interbreeding between early hominin species was 'the norm'

  • Study found a saliva protein in modern sub-Saharan Africans to be very distinct
  • This suggests the ancient species interbred with another archaic human species
  • But, there are no fossils linked to this discovery, making it a 'ghost' species


Ancient human ancestors that can be traced to populations alive today may have engaged in ‘sexual rendezvous’ with a ‘ghost’ species of archaic humans.

In a new analysis of a protein found in saliva, researchers discovered evidence of archaic admixture in modern people living in sub-Saharan Africa, indicating that another species had contributed to the genetic material of their ancestors.

The experts say it appears that interbreeding was common among early hominin species – but, with no fossils of the mysterious species in question, it’s considered a ‘ghost.’

‘It seems that interbreeding between different early hominin species is not the exception – it’s the norm,’ said Omer Gokcumen, PhD, an assistant professor of biological sciences at the University at Buffalo’s College of Arts and Sciences.

‘Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva.

‘When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern day Sub-Saharan African population.’

The researchers were investigating the purpose and origins of the MUC7 protein.

This protein is, in part, responsible for the slimy consistency of saliva, and helps it to bind to microbes.

http://www.dailymail.co.uk/sciencetech/article-4719274/Biologists-clues-ghost-species-ancient-human.html

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Frankly Kemet
Banned
Member # 22882

Rate Member
Icon 1 posted      Profile for Frankly Kemet         Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Ish Gebor:
quote:
Originally posted by Frankly Kemet:
I thought Neanderthal arose out of Homo erectus of OoA?

Do you have studies done on the Homo Erectus?
Here is what some other "flamers" think.

 -

Patterns of hominid evolution and dispersal in the Middle Pleistocene

Posts: 115 | From: NYC | Registered: Feb 2018  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
Fourty2Tribes, can you write a clear an concise sentence saying exactly what xxwhyman is right about
Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Ish Geber
Member
Member # 18264

Member Rated:
4
Icon 1 posted      Profile for Ish Geber     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Frankly Kemet:
quote:
Originally posted by Ish Gebor:
quote:
Originally posted by Frankly Kemet:
I thought Neanderthal arose out of Homo erectus of OoA?

Do you have studies done on the Homo Erectus?
Here is what some other "flamers" think.

 -

Patterns of hominid evolution and dispersal in the Middle Pleistocene

Interesting, but it is more a matter of checkers than flamers.

Homo Erectus and Homo Heidelbergensis are associated with the Acheulean industry. This paper you've posted has has three instances.

1) At Casablanca in Morocco, stone tools document the spread of the same species northward. Acheulean artifacts recovered at Thomas Quarry 1 are from late Early Pleistocene deposits dating to about 1.0 Ma (Raynal et al., 2001).

2) Although there is disagreement about taxonomy, it can be argued that the new species is appropriately called Homo heidelbergensis. Key questions awaiting resolution concern the geographic region where this taxon originated, its subsequent dispersal, and the role played by these populations in the spread of Acheulean stone technologies. Other issues are phylogenetic, and it is important to clarify the relationship of Homo heidelbergensis to Neanderthals and recent humans.

3) Saragusti and Goren-Inbar (2001) suggest that the lack of direct links between the Acheulean of Ubeidiya and the later industry at Gesher Benot Ya'aqov may be explained as a result of multiple pulses of people or ideas out of Africa and into the Levant, during the latest Early Pleistocene (see also, Goren-Inbar and Saragusti, 1996).


Here is more on the Acheulean industry.


Lithic Landscapes: Early Human Impact from Stone Tool Production on the Central Saharan Environment



The earliest hand axes, such as those found with Homo erectus in Bed II at Olduvai Gorge in Tanzania, were crude pointed bifaces: chips were removed from both sides of a core by rapping it against a set “anvil” stone to form a sinuous cutting edge all around.

https://www.britannica.com/topic/Acheulean-industry


Homo erectus - A Bigger, Smarter, Faster Hominin Lineage


While fossil remains from H. erectus are found in Africa, like those of earlier hominins, they have also been identified at fossil sites widely dispersed across Eurasia (Figure 1, Table 1).

 -

https://www.nature.com/scitable/knowledge/library/homo-erectus-a-bigger-smarter-97879043


 -


http://sitn.hms.harvard.edu/flash/2012/issue132a/

Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by the lioness,:
Fourty2Tribes, can you write a clear an concise sentence saying exactly what xxwhyman is right about

We share a genetic signature with Neanderthals. It comes from a common ancestor. It shows stronger in older, bottle-necked, and isolated populations. Its weaker in the more genetically diverse.  -

Bottle-necked people are more Neanderthal because they are less homo-sapiens/whatever archaic, not because every OoA groups passed through a Neanderthal orgy. I remember having some fun with xyyman because he was late to realize that Neanderthals are used as a last chance multi-regional argument.

I didn't know the depths of it.

The same person who made Tut and Nefertiti white did this to Neanderthals.
 -

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
quote:
Originally posted by the lioness,:
[qb] Fourty2Tribes, can you write a clear an concise sentence saying exactly what xxwhyman is right about

We share a genetic signature with Neanderthals. It comes from a common ancestor. It shows stronger in older, bottle-necked, and isolated populations. Its weaker in the more genetically diverse.  -

Bottle-necked people are more Neanderthal because they are less homo-sapiens/whatever archaic, not because every OoA groups passed through a Neanderthal orgy. I remember having some fun with xyyman because he was late to realize that Neanderthals are used as a last chance multi-regional argument.

I didn't know the depths of it.


That reasoning is faulty and would need a chart that included Neanderthals
Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
I said its from a common ancestor. For the lurkers I will include.

 -

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
that chart is still no good. It needs to show Africans, Eurasians (or equivalent name) and Neanderthal

If you can't find one we will make one

Also the chart you posted does not illustrate the point you are trying to make even in that haplogroup layout

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
I don't see why when Neanderthals and Sapiens were both Heidelbergensis or Erectus.
Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
http://news.bbc.co.uk/2/hi/sci/tech/8660940.stm

 -

here is a BBC news chart. Note yoruba have some trace Neanderthal
and the Neanderthal admixture in the Papuan is more specifically the similar to Neanderthal, Denisova hominid

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
French, Chinese and Papuans dont share a common OoA ancestor though. And its not just Yoruba. I could understand Yoruba through back migration from the Massai or maybe other eastern ancestors. Thats what I originally thought. What changed my mind are all those 23andme test where people like this who are 98% SSA  - from central Africa.
Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
 -


quote:
Originally posted by Fourty2Tribes:
French, Chinese and Papuans dont share a common OoA ancestor ...

Bottle-necked people are more Neanderthal because they are less homo-sapiens/whatever archaic


what do you mean Bottle-necked people are more Neanderthal because they are less homo-sapiens/whatever archaic?


quote:
Originally posted by Fourty2Tribes:

Bottle-necked people are more Neanderthal because they are less homo-sapiens/whatever archaic, not because every OoA groups passed through a Neanderthal orgy


what you are saying doesn't make sense, If you take out the dark green segment you remove the Neanderthal orgy admixture. And the late stage Neanderthal is a dead end having never mixed with humans

Then the reverse would be true without that Neanderthal admixture Africans would be closer to the common ancestor of the Neanderthal

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
What changed my mind are all those 23andme test where people like this who are 98% SSA  - from central Africa. [/QB]

This is possibly a person with 2% non African ancestry and the person back in the ancestry who was non African had 58 Neanderthal variants. Thus the 98% person has these variants at a frequency much lower than 1%, at trace levels. Some Yoruba have shown this
Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Ish Geber
Member
Member # 18264

Member Rated:
4
Icon 1 posted      Profile for Ish Geber     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
"More generally, it has often been suggested that there is an extant tropical belt of human populations that anatomically resemble sub-Saharan Africans (with 'racial' features such as very dark skin, curly hair and so on). They include some southern Indians, the Andamese, the so-called Negritos of the Phillipines (Aeta/Agta) and the Malay Penisula (Semang), Papuans and Aboriginal Australians. These people, it as suggested, might be the survivors of a 'southern coastal route' from the Horn of Africa along the tropical coastline through to Southeast Asia and Australia (Nei and Roychoudhury 1992). The bulk of EUrasian populations were then suggested to be the survivors if a 'northern route': out of Egypt into the 'Levantine corridor', and thence into both Europe and Asia (Lahr 1996).'"
-- Hans-Jürgen Bandelt et. 2006. EDS. Human Mitochondrial DNA and the Evolution of Homo sapiens. p. 234
Posts: 22234 | From: האם אינכם כילדי הכרית אלי בני ישראל | Registered: Nov 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by the lioness,:
This is possibly a person with 2% non African ancestry and the person back in the ancestry who was non African had 58 Neanderthal variants. Thus the 98% person has these variants at a frequency much lower than 1%, at trace levels. Some Yoruba have shown this

It is lower than 1% Neanderthal. Its probably 0.2% or 0.3% but I have seen African Americans that are 15% European with less variants.

He is from Burundi. He isn't Yoruba or San. I think he is just less diverse than most Africans [Wink] .

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
quote:
Originally posted by the lioness,:
This is possibly a person with 2% non African ancestry and the person back in the ancestry who was non African had 58 Neanderthal variants. Thus the 98% person has these variants at a frequency much lower than 1%, at trace levels. Some Yoruba have shown this

It is lower than 1% Neanderthal. Its probably 0.2% or 0.3% but I have seen African Americans that are 15% European with less variants.

He is from Burundi. He isn't Yoruba or San. I think he is just less diverse than most Africans [Wink] .

 -

.

yes but this model is saying that people who have Neanderthal ancestry due to neanderthals interbreeding with humans and this would have occurred more than 30,000 years ago since Neanderthals died out after that


 -

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
I know the model. I'm saying the model is wrong. A SSA African living 35,000 years ago would have more Neanderthal variants too. They would be closer to the ancestral split. It would be relatively fewer than Oase because Africans have more spoonfuls of Homo-Sapien and/or whatever archaics.

That is why I didn't include Neanderthals in my model. This is a signature from an ancestral connection not a sexual connection.

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
I know the model. I'm saying the model is wrong. A SSA African living 35,000 years ago would have more Neanderthal variants too. They would be closer to the ancestral split. It would be relatively fewer than Oase because Africans have more spoonfuls of Homo-Sapien and/or whatever archaics.

That is why I didn't include Neanderthals in my model. This is a signature from an ancestral connection not a sexual connection.

The common ancestor splits into homo sapiens and Neanderthal.
In the beginning of the split both of them are only slightly different, thousands of years later the common ancestor has fully developed int the two types, Neanderthal and Homo Sapien.
African homo sapiens are closer to that common ancestor than later OOA populations.
That means according to what you said before it would be Africans closer to Neanderthal than later homo sapiens who bottle necked as the OOA populations.
Without any interbreeding than the Africans are closer, obviously, you came to the wrong conclusion of your own premise.

The only way possible a later homo sapien population and OOA population to have higher percentage of Neanderthal would be for interbreeding to have occurred outside of Africa

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
Everyone is equal distance from the split. We have all had the same time to mutate yet Africans have a lot more mutations to divvy between other Africans which then dilutes the percentage of the Neanderthal signature left from the split.

 -

Just think of one of the colors as being the Neanderthal signature left from a shared ancestor. You don't need interbreeding for OoA populations to have a higher percentage. This explains why Africans have a slight percentage of Neanderthal that is proportionality as small compared to OoA populations as their diversity is high. This also explains why OoA groups that are closer to Africans than other bottlenecks still have a higher percentage of Neanderthal.

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
Everyone is equal distance from the split. We have all had the same time to mutate yet Africans have a lot more mutations to divvy between other Africans which then dilutes the percentage of the Neanderthal signature left from the split.


No, what you are saying is built on a false premise.
In your scenario there was no admixture.

There was a common ancestor that then split into homo sapiens and Neanderthal

After that point there is ZERO signature of neanderthal in homo sapiens.

The common ancestor is not Neanderthal
It is a state prior to the evolution of a Neanderthal. A split is not a single mutation that then instantly produces a Neanderthal. It is a slow evolutionary process constrained by different environments and gradual selection.

The signature they find in some homos sapiens is not merely their ancestor

The signature is something that had evolved to be distinguishable for the common ancestor a Neanderthal (and Denisova)

Any humans with a Neanderthal traces would be a result of admixture with them

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by the lioness,:
No, what you are saying is built on a false premise.
In your scenario there was no admixture.

There was a common ancestor that then split into homo sapiens and Neanderthal

Now you get it.

quote:

After that point there is ZERO signature of neanderthal in homo sapiens.

http://www.pbs.org/your-inner-fish/home/
We still have genes from our shared ancestors with Fish. We got our bones from them.
Africans are just a little bit further from Fish because they drank extra spoonfuls of that good ole Homo-Sapien.

quote:

The common ancestor is not Neanderthal
It is a state prior to the evolution of a Neanderthal. A split is not a single mutation that then instantly produces a Neanderthal. It is a slow evolutionary process constrained by different environments and gradual selection.

The common ancestor had enough Neanderthal genes to be a simulation Neanderthal when you don't have real admixture to compare it to.

quote:

The signature they find in some homos sapiens is not merely their ancestor

The signature is something that had evolved to be distinguishable for the common ancestor a Neanderthal (and Denisova)


There may have been admixture with Denisovans. I say that because supposedly its spiked in Melanesians. That said all we have is one bone fragment on Denisovans. I've seen no evidence that the signature from what was shared can be distinguished from what could be gained through admixture.
Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
The common ancestor had enough Neanderthal genes to be a simulation Neanderthal when you don't have real admixture to compare it to.

The Neanderthal and human have genes of the common ancestor.

But what makes a Neanderthal a Neanderthal or a Homo sapien a Homo sapien are the new mutations they have that are NOT of the common ancestor

The homo sapien and the Neanderthal both have genes of the common ancestor

The common ancestor HAD none of the genes that distinguish a Neanderthal or a homo sapien from them


And it is the unique genes that made a Neanderthal a Neanderthal that are detected in certain humans in small virtually inconsequential frequencies

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Elmaestro
Moderator
Member # 22566

Member Rated:
5
Icon 1 posted      Profile for Elmaestro     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by the lioness,:
The Neanderthal and human have genes of the common ancestor.

But what makes a Neanderthal a Neanderthal or a Homo sapien a Homo sapien are the new mutations they have that are NOT of the common ancestor

The homo sapien and the Neanderthal both have genes of the common ancestor

The common ancestor HAD none of the genes that distinguish a Neanderthal or a homo sapien from them


And it is the unique genes that made a Neanderthal a Neanderthal that are detected in certain humans in small virtually inconsequential frequencies

Here's a thought experiment. We have not sequenced the common ancestor of Neanderthals and HomoSapiens. So our basis for Homosapien Divergence is based on reference Human Genomes. How do you know that the lack of "Neanderthal genes" in our reference genomes weren't present in the common ancestor of Archaics?
Posts: 1781 | From: New York | Registered: Jul 2016  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
Well said Elmaestro. You can tell that is unknown because people keep finding Neanderthal variants in unmixed Africans and asking this question.
http://www.unz.com/pfrost/were-there-neanderthals-in-africa/

quote:
Perhaps this “Neanderthal” admixture was simply admixture with a Neanderthal-like population within Africa itself.
My answer is that Ancient Africans were a Neanderthal-like population, A Denosovan-like population, a homo Erectus-like population a Heidelbergensis-like population with extra spoonfuls of homo-sapien-sapien.
Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
the lioness,
Member
Member # 17353

Rate Member
Icon 1 posted      Profile for the lioness,     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by Fourty2Tribes:
Well said Elmaestro. You can tell that is unknown because people keep finding Neanderthal variants in unmixed Africans and asking this question.
http://www.unz.com/pfrost/were-there-neanderthals-in-africa/

quote:
Perhaps this “Neanderthal” admixture was simply admixture with a Neanderthal-like population within Africa itself.
My answer is that Ancient Africans were a Neanderthal-like population, A Denosovan-like population, a homo Erectus-like population a Heidelbergensis-like population with extra spoonfuls of homo-sapien-sapien.
here is more form John Hawkes who you refer to in the link:

http://johnhawks.net/weblog/reviews/genetics/mtdna/mtdna-introgression-selection-heat-2018.html

What explains mtDNA introgression among archaic human populations?

30 Jan 2018
In case anyone still wonders how variation in mitochondria might have been important to Neandertals and other archaic humans:
quote:
A bizarre find: Tiny powerhouses in your cells run at 122 degrees
The researchers grew human kidney cells and skin cells in petri dishes, which they kept at 38 degrees Celsius. Into these cells the scientists inserted a new type of fluorescent dye, which brightens as it cools. When the mitochondria became active, the fluorescence dimmed. This indicated that the temperature within the mitochondria rose between seven and 12 degrees Celsius, or an average of 10 degrees, as reported in the journal PLOS Biology on Thursday.

Previous researchers have suspected that human variation in mtDNA might relate to the tradeoff of heat production and ATP efficiency in mitochondria, with advantages for some mtDNA haplogroups in cold-adapted human populations. Circumstantial evidence for this hypothesis has been known for more than a decade, and I wrote about it back in 2005: “Mitochondrial DNA adaptations in living human populations”.

Even if important differences in mitochondrial function exist between human populations, mitochondrial DNA may not be the cause. Most of the genes that influence mitochondrial function are encoded in the nuclear genome, not the mtDNA. Yet some of the genes on the mtDNA do influence mtDNA function in ways that may have been selected in humans. Also, the mtDNA is the only part of the eukaryotic genetic complement that must function inside the mitochondrion itself, exposing it to a distinctive intracellular environment with its own possible effects on transcription.

The story of mtDNA in archaic humans has become more and more intricate. The earliest-known members of the Neandertal lineage, from Sima de los Huesos, Spain, have an ancient haplogroup that has not been found in later Neandertals or modern humans. This clade has been identified in Denisovans, although the variants in the Denisovan individuals known so far are fairly distant from the chronologically earlier Sima de los Huesos individuals.

Meanwhile, later Neandertals share a mtDNA clade that connects them more closely to the common mtDNA ancestor of modern humans, including all living African and non-African people. The origin of this clade is not known. It may have originated in Africa and have been exchanged into Neandertals by introgression some 250,000 years ago or more. Alternatively, it may have originated elsewhere and introgressed into both African and Neandertal populations. The extensive introgression of this mtDNA variant, in the absence of strong evidence of nuclear genome introgression at the same time, suggests that natural selection may have driven the mtDNA introgression.

No living people have been found with a mtDNA haplotype within the variation found within either the Neandertals or the Denisovans. Instead, everyone living today belongs to a subclade that originated within the last 300,000 years.

It is not currently clear whether this mitochondrial Eve lived before the populations that gave rise to all modern humans began to differentiate from each other. That differentiation began before 300,000 years ago, according to recent studies of African genetic variation from the nuclear genome. That’s earlier than most estimates of the date of the common mtDNA ancestor.

Within Africans today is much more mtDNA clade diversity than outside Africa. Throughout the pre-Columbian populations of most of the world, all people have mtDNA sequences that belong to two narrow branches of the mtDNA tree, which seem to have originated in the last 100,000 years. It is within these low-variation branches that a few functional variants have been found that might differentiate cold-climate populations from others. The adaptive story that has been examined so far for mtDNA does not relate to the much greater mtDNA variation that still exists within sub-Saharan African peoples.

I’ve been interested in mtDNA selection for a long time, and wrote about it in a 2006 paper: “Selection on mitochondrial DNA and the Neanderthal problem”.

There is a lot left to learn, which will no doubt leave today’s knowledge looking pretty inadequate. But what seems like mtDNA total replacement within Neandertals was a pretty striking event, and deserves more consideration as a possible case of adaptive evolution.

Posts: 42918 | From: , | Registered: Jan 2010  |  IP: Logged | Report this post to a Moderator
Forty2Tribes
Member
Member # 21799

Rate Member
Icon 1 posted      Profile for Forty2Tribes   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
Interesting. What do you think about this article?

https://www.nature.com/articles/ncomms16046

Posts: 1254 | From: howdy | Registered: Mar 2014  |  IP: Logged | Report this post to a Moderator
   

Quick Reply
Message:

HTML is not enabled.
UBB Code™ is enabled.

Instant Graemlins
   


Post New Topic  New Poll  Post A Reply Close Topic   Feature Topic   Move Topic   Delete Topic next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:


Contact Us | EgyptSearch!

(c) 2015 EgyptSearch.com

Powered by UBB.classic™ 6.7.3