What is the truth about "junk" parts in the genetic material of humans?

October 25, 2022

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What is the truth about "junk" parts in the genetic material of humans? The latest version of the list of human gene names contains 43,238 genes, of which 19,369 are protein-coding genes, and the rest are located in what was formerly called "junk genetic material". The discoveries of scientists in the middle of the last century about the genetic material of living organisms represented a turning point in our understanding of biology, as it opened a completely different horizon for the study and understanding of biological systems and the molecular or structural level of it. Determining the structure of deoxygenated DNA - known for short as "DNA" (DNA) - is the most important of these discoveries. This was done by the British chemist Rosalind Franklin, the American biologist James Watson and the British physicist Francis Crick; This effort resulted in the most famous model in science, the DNA synthesis model. Following these discoveries is another important discovery by the American cytogeneticist Barbara McClintock, who discovered mobile genetic factors, a discovery that was not widely accepted at the time, before the scientific community understood the importance of what she found and was awarded the Nobel Prize for it in 1983. Unexpected results The second milestone in the field of molecular biology was the Human Genome Project, which began in the late 1990s with the aim of producing the first complete sequence of the human genome, and the entire genetic material of an organism. This project published the first draft of the human genome in 2003, covering about 90% of it, and took several years at an estimated cost of $3 billion. It took about 20 years to complete the remaining 10% of the genome, and the journal "Science" published in the April 2022 issue the closest-complete version of the human genome for the first time. The first draft and subsequent improvements opened unprecedented prospects for analyzing the genetic structure of humans, the most important of which is the identification of genes and their functions. The surprising result was that only a very small percentage of the human genome found its function in the period following the publication of the first draft, while more than 90% of its sequences remained without a known function. The portion whose function was recognized was mostly protein-coding genes; Any containing instructions for the production of proteins. The rest of the genome was termed as non-coding protein sequences, and was then considered nonfunctional, or of unknown function. Here, a theory came to mind by the Japanese-American evolutionary biologist Suzumo Ono - published in 1972 - which saw that the non-coding protein sequences in the genomes of living organisms are a remnant of the evolution process that occurred in living organisms over thousands of years; Thus it is nothing more than "junk"; The cells kept the useful (protein-producing) part functioning, and those other parts were left over from the evolution process. He called it "junk genetic material". Two giant projects The fact that these sequences contained functional parts (that perform regulatory functions) still haunted the scientific community, and the "genetic junk theory" seemed too simple and straightforward; Therefore, efforts to study non-coding protein sequences began, and evidence began to accumulate that parts of them perform very important vital functions in regulating the production of proteins within cells. These efforts combined into two giant projects: the Encyclopedia of DNA Elements Project, and the Epigenome Roadmap Project. The first project was concerned with the study of non-functionally encoded sequences, and an attempt to know the functions and mechanisms of work of the genetic material in these parts. The project published its results for the first time in the journal Nature in 2012. The journal also dedicated a mini -site to the research papers resulting from the project, which have nearly 50 papers so far. The second project was concerned with studying all the chemical changes and modifications that occur to any part of the genome, and modify its function, especially in the non-coding protein sequences. The results of this project were also featured in Nature in 2015 on a microsite . Junk that is no longer Surprisingly, the two projects were able to determine the functions of nearly 85% of the human genome, including non-coding sequences; This weakened the "genetic junk" theory and the idea that these sequences were just an accumulation of unnecessary genetic material that occurred during the evolution process. The two projects found that large portions of these sequences perform regulatory functions; Such as activating, inhibiting, starting and stopping the processes of producing proteins, and they also found that there are parts of these sequences that move from their position to inside the protein-encoding genes to move them from the state of latency to the state of activity, which is exactly the mobile genetic elements that were first described by McClintock in the middle of the last century, and they also found Also parts of the genome are active, but they haven't found their function or reason for their activity yet. Over the following years, scientists used the results of the two projects to provide a better understanding of the functions and components of the human genome, their role in diseases, their interaction with drugs and other important applications, including what was presented by the Tumor Genome Analysis Project, which provided an analysis of cancer-causing mutations in non-coding sequences; In a study, the largest of its kind to date, as it included more than 2,650 complete genomes taken from cancer cells, the journal Nature published the results of the project in 2020. Another study from the same project found a strong relationship between 122 non-protein-coding LncRNA (LncRNA) genes and tumorigenesis, and its results were published in the same year. On the other hand, some evolutionary biologists rejected the results of the two projects, considering that the mere presence of activity in a region of the genome is not sufficient evidence that it performs a function. Despite this, we find that the term “junk genetic material” has been decreasing continuously since 2014, as the PubMed research database indicates that the term was mentioned in 80,691 research papers from 1972 until today, and reached a peak In 2013, it amounted to nearly 4,000 papers, then its mention decreased in research published annually, until it reached 1,272 papers in 2022. The latest version of the list of human gene names issued by the Gene Nomenclature Committee of the National Human Genome Research Institute in the United States contains 43,238 genes, of which 19,369 are protein-coding genes, while the rest (more than 23 thousand genes) are located in what was formerly called "Article genetic scrap".

The latest version of the list of human gene names contains 43,238 genes, of which 19,369 are protein-coding genes, and the rest are located in what was formerly called "junk genetic material".

The discoveries of scientists in the middle of the last century about the genetic material of living organisms represented a turning point in our understanding of biology, as it opened a completely different horizon for the study and understanding of biological systems and the molecular or structural level of it.

Determining the structure of deoxygenated DNA - known for short as "DNA" (DNA) - is the most important of these discoveries.

This was done by the British chemist Rosalind Franklin, the American biologist James Watson and the British physicist Francis Crick; This effort resulted in the most famous model in science, the DNA synthesis model.

Following these discoveries is another important discovery by the American cytogeneticist Barbara McClintock, who discovered mobile genetic factors, a discovery that was not widely accepted at the time, before the scientific community understood the importance of what she found and was awarded the Nobel Prize for it in 1983.

Unexpected results

The second milestone in the field of molecular biology was the Human Genome Project, which began in the late 1990s with the aim of producing the first complete sequence of the human genome, and the entire genetic material of an organism.

This project published the first draft of the human genome in 2003, covering about 90% of it, and took several years at an estimated cost of $3 billion.

It took about 20 years to complete the remaining 10% of the genome, and the journal "Science" published in the April 2022 issue the closest-complete version of the human genome for the first time.

The first draft and subsequent improvements opened unprecedented prospects for analyzing the genetic structure of humans, the most important of which is the identification of genes and their functions.

The surprising result was that only a very small percentage of the human genome found its function in the period following the publication of the first draft, while more than 90% of its sequences remained without a known function.

The portion whose function was recognized was mostly protein-coding genes; Any containing instructions for the production of proteins.

The rest of the genome was termed as non-coding protein sequences, and was then considered nonfunctional, or of unknown function.

Here, a theory came to mind by the Japanese-American evolutionary biologist Suzumo Ono - published in 1972 - which saw that the non-coding protein sequences in the genomes of living organisms are a remnant of the evolution process that occurred in living organisms over thousands of years; Thus it is nothing more than "junk"; The cells kept the useful (protein-producing) part functioning, and those other parts were left over from the evolution process. He called it "junk genetic material".

Two giant projects

The fact that these sequences contained functional parts (that perform regulatory functions) still haunted the scientific community, and the "genetic junk theory" seemed too simple and straightforward; Therefore, efforts to study non-coding protein sequences began, and evidence began to accumulate that parts of them perform very important vital functions in regulating the production of proteins within cells.

These efforts combined into two giant projects: the Encyclopedia of DNA Elements Project, and the Epigenome Roadmap Project.

The first project was concerned with the study of non-functionally encoded sequences, and an attempt to know the functions and mechanisms of work of the genetic material in these parts. The project published its results for the first time in the journal Nature in 2012. The journal also dedicated a mini -site to the research papers resulting from the project, which have nearly 50 papers so far.

The second project was concerned with studying all the chemical changes and modifications that occur to any part of the genome, and modify its function, especially in the non-coding protein sequences. The results of this project were also featured in Nature in 2015 on a microsite .

Junk that is no longer

Surprisingly, the two projects were able to determine the functions of nearly 85% of the human genome, including non-coding sequences; This weakened the "genetic junk" theory and the idea that these sequences were just an accumulation of unnecessary genetic material that occurred during the evolution process.

The two projects found that large portions of these sequences perform regulatory functions; Such as activating, inhibiting, starting and stopping the processes of producing proteins, and they also found that there are parts of these sequences that move from their position to inside the protein-encoding genes to move them from the state of latency to the state of activity, which is exactly the mobile genetic elements that were first described by McClintock in the middle of the last century, and they also found Also parts of the genome are active, but they haven't found their function or reason for their activity yet.

Over the following years, scientists used the results of the two projects to provide a better understanding of the functions and components of the human genome, their role in diseases, their interaction with drugs and other important applications, including what was presented by the Tumor Genome Analysis Project, which provided an analysis of cancer-causing mutations in non-coding sequences; In a study, the largest of its kind to date, as it included more than 2,650 complete genomes taken from cancer cells, the journal Nature published the results of the project in 2020.

Another study from the same project found a strong relationship between 122 non-protein-coding LncRNA (LncRNA) genes and tumorigenesis, and its results were published in the same year.

On the other hand, some evolutionary biologists rejected the results of the two projects, considering that the mere presence of activity in a region of the genome is not sufficient evidence that it performs a function.

Despite this, we find that the term “junk genetic material” has been decreasing continuously since 2014, as the PubMed research database indicates that the term was mentioned in 80,691 research papers from 1972 until today, and reached a peak In 2013, it amounted to nearly 4,000 papers, then its mention decreased in research published annually, until it reached 1,272 papers in 2022.

The latest version of the list of human gene names issued by the Gene Nomenclature Committee of the National Human Genome Research Institute in the United States contains 43,238 genes, of which 19,369 are protein-coding genes, while the rest (more than 23 thousand genes) are located in what was formerly called "Article genetic scrap".