Scientists have performed the most complex statistical examination to date of our genetic lines back to the first mother of all humans alive today. The research may help scientists understand the history of life on Earth and some of the basic mechanisms of evolution
Mitochondria are tiny organelles found inside every human cell and have their own genome. All animals inherited their mitochondria, and with it the mitochondrial DNA from their offspring. Photo: NIH
The most comprehensive statistical analysis done so far of the genetic connections of the human race led to the "mitochondrial farm" - the ancestral mother of all humans alive today - and confirmed that she lived about 200 thousand years ago. The Rice University study was based on a side-by-side comparison of 10 human gene models, with each of them supposed to independently determine when an animal lived, using a series of estimates about the way humans migrated, spread and spread across the planet. The study is available online in the journal Theoretical Population Biology.
"Our findings highlight the importance of taking into account the random nature of population processes such as growth and extinction," said one of the study's authors Mark Kimmel, professor of statistics at Rice University. " Glacial deterministic models, including some that tried to date the time of the mitochondrial farm did not fully take into account all these random processes".
The quest to date the mitochondrial eve (mtEve) is an example of how scientists have explored the genetic past to learn more about mutations, selection and other genetic processes that play key roles in disease. "This is why we are interested in patterns of genetic variation in general," Kimmel said. "They are very important for drug development."
For example, the way scientists try to date mtEve relies on modern genetic techniques. Genetic profiles of random blood donors are compared and based on similarities and differences between certain genes, the scientists can assign a number that describes the degree to which any two donors are related to each other.
Using the mitochondrial genome to gauge genetic kinship is the way for geneticists to simplify the task of finding ancestors who lived long ago. This is due to the fact that the human genome contains over 20 genes, and comparing all the differences among so many genes to find distant family kinship is problematic even with today's fast and large supercomputers.
But mitochondria - tiny organelles that serve as the energy factories inside every human cell have their own genome. Besides the fact that it contains 37 genes that hardly change, they contain a rapidly changing "hypervariable" region. The rapid changes in this area produce for the scientists a calibrated molecular clock to compare with the age of modern humanity. Since each person inherits their mitochondrial genome from their mother, all mitochondrial lineages are maternal.
To deduce Eve's age the scientists had to transform the kinship ties between the random blood donors into a time scale.
"The differences between the gene sequences need to be translated into a framework in which to measure how they have evolved over time," said Krzysztof Krayan, deputy head of the Informatics Institute at the Silesian University of Technology in Gliwice, Poland. "And how they evolved over time depending on the evolutionary model used. So, for example, what is the rate of genetic mutations and is this rate of change uniform over time? And what about the process of random loss of genetic variation, which we call genetic drift?"
Within any such model, the answers to these questions take the form of coefficients - numerical constants that are inserted into the equation that returns the answer to when an animal experienced mitochondrial.
Each model has its own assumptions, and each assumption has mathematical implications. To complicate matters further, some assumptions are not valid for human populations. For example, some models assume that the population size never changes. This is not true for humans, whose population has been growing rapidly for at least several thousand generations. Other models assume perfect mixing of genes, meaning that every two people anywhere in the world have an equal chance of producing offspring.
According to Kerian, the human genetic models have become more complicated over the past XNUMX years or so as theorists have tried to correct the wrong assumptions. But some of the corrections such as adding branching processes that try to capture the dynamics of population growth in the first human migrations - are very complex. This raises the question of whether less complex models will be good enough to capture what actually happened.
"We wanted to see how sensitive the models' assumptions were," Kimmel said. "We found that all the models that considered the random size of populations, such as different branching processes - gave similar estimates. This is reassuring, because it shows that improving the model assumptions, beyond a certain point, may not be important when it comes to looking at the big picture. "
15 תגובות
Eran:
This idea of a "mitochondrial mother" is a simple idea that requires mathematical considerations.
Think of all the women alive today.
Let's say its size is X.
Now think about the group of mothers of these women.
Obviously, the size of this group is smaller than X (because every contemporary woman has only one mother while there are mothers who gave birth to several daughters).
So we say that the size of the motherhood group of contemporary women is Y and we already know that Y is smaller than X.
Now let's think about the group of mothers of these women.
This group will be of size Z which is smaller than Y for exactly the same reason.
It is therefore clear that if you go far enough back in time you will reach a group where there is only one woman from whom all the women alive today are descendants.
Uncle:
You are quick to state that you have not been understood.
At least one of the answers you received is very relevant to your question and that is the recommendation for the book "The Fish Within".
There are many books in this genre and I can give you a very long list, but if you want an answer to the specific question you asked - "The Fish Within" is a good answer and another book, which has not yet been mentioned in this discussion, and which answers your question even better is the book Endless Forms Most Beautiful
For Sunday, Bayer Vaadz
of this channel is called this site two hundred years ago
Leshahar and others
Thanks for the recommendations
Maybe my question in 8 is from a slightly different area and not clear enough.
I will put it this way:
In each generation, material is transferred physically: in the last generation, since we breastfeed (and even before that), sperm + egg.
But it all started long before that - a single cell that began to divide.
My question is what "material" do we have from him?
Iran - there were also other women then; But it turned out that we were all sons of a farm. The descendants or descendants of the descendants of the others did not leave dynasties that continued to the present day.
I don't understand a single thing about it...
Ok, there is one original mother for all of us... so who did her children sleep with... and if so... how come they didn't have genetic defects like we have at the wedding of relatives...
That's what's always strange to me... how only one mother manages to split into many... it's not like we're amphibians like frogs and spawn thousands of eggs...
someone?? explanation?
to dawn
Get a recommendation
2 books I liked in the genre
Precisely the weak survive by Dr. Sharon Moalem
Seeds are from men and eggs are from Joe Quirk's women
To David
I highly recommend a book called The Fish Within for starters. I just finished it and it was fascinating. This will give you our/mammal connection to the fish and also some background on the origin of life
But before anything else, go to the book "The Selfish Garden" a little old but strong exactly on the source of life
And the blind watchmaker is also recommended
I would appreciate further recommendations if anyone has read anything in this genre.
By the way, regarding the primordial mother, there is an amazing book called 7 Farm Daughters. Also talks about mapping mothers based on mitochondrial DNA
A question that is not so related to the article but interests me: Can we say that we have a material connection to the first cell that was created 3.5 billion years ago? That is, in some way we in our bodies carry our ancestors up to the first generation of the beginning of life?
Of course these signs of the aliens exist where Nibiru exists - in Sitchin's imagination. The Nazca lines and the pyramids are human works, in the ancient world if a king goes crazy and wants something, the slaves will be found to build it for him with the technologies available at that time. You don't need extraterrestrials for that.
I half contradict those who said that Zechariah is an idiot because extraterrestrial signs were discovered in the area of the pyramids in America such as the skulls of the "children of the stars" and also the Nasca lines {the natives did not have engineering tools good enough to build the pyramids and in fact to this day there are none}
""Zacharia Sitchin is an idiot. He invented all the things he claims to have discovered, and because of him we suffer today from Nibiru's nonsense and the mess around 2012."
!!!
Bless you my father
It's not about the article but about the idiots. Start spreading the email again about Mars coming closer to us and showing the size of the moon. get ready
The writer Zakaria Sitchin is an idiot. He invented all the things he claims to have discovered, and because of him we suffer today from Nibiru's nonsense and the mess around 2012.
surprising.
This is exactly what the ancient Guardian Tablets record -
The beginning of man from about 200-250 thousand years ago
Only not due to natural evolution but through Hinduization by the Anunnaki (aliens?) of their DNA with
The natives (primates?)
This number (200,000) brings us to the beginning of the existence of the homo sapiens sapiens - so what wonder then that a mitochondrial animal lived. Or in another form of expression - things support each other.
However, in a comprehensive investigative program on the National Geographic Channel, I learned about a common ancestor later. From genetic mapping (supposing a certain mutation) of the Y (male) chromosome, it was found that the common ancestor of all men in the world lived about sixty thousand years ago. He was of course black-skinned living in Africa - all people were like that then. A common ancestor of half of the men in the world, lived about forty thousand years ago (if I remember correctly - somewhere on the border of Europe and Asia).