The following essay is covered in The Conversation, an online publication.

According to new research published by my colleagues and I, the remnants of ancient viral pandemics are still active in healthy people.

Human retroviruses, or HERVs, make up 8% of the human genome, left behind as a result of infections millions of years ago. The way they replicate made them part of the human genome.

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The ancient retroviruses had to insert their genetic material into their host. This type of genetic material isn't passed down from generation to generation. Some ancient retroviruses were able to transmit their genes to future generations. By targeting germ cells, these retroviruses became incorporated into human ancestral genomes over the course of millions of years.

Active viral genes in the human genome

The proviruses insert their genomes into their hosts. Around 30 different kinds of human retroviruses are present in people today. Over the course of evolution, humanity has been subjected to many different types of diseases. Chimpanzees, gorillas, and other primate genomes have become fixed in the human genome, which scientists think was the reason why these viruses once spread widely.

Our lab and others have shown that HERV genes are active in tumors and human embryo development. It's still not known how active HERV genes are in healthy tissues.

To answer the question, our lab focused on one group of HERVs. The group went extinct less than 5 million years ago. Some of the proviruses within the human genome are still capable of making viral proteins.

We looked at the genetic material in the database and found a lot of tissue samples. We were able to find 37 different HML-2 proviruses that were still active by looking for the same sequence in the genomes of each of them. We analyzed 54 tissue samples and found some evidence of proviruses. Each tissue sample contained genetic material from at least one proviruses.

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The role of HERVs in human health and disease

A lot of attention has been given to the fact that thousands of pieces of ancient viruses still exist in the human genome and that they can cause breast cancer and AIDS-like diseases in animals.

The genetics of human retroviruses are still being studied. The presence of HERV genetic material in disease tissue has been linked to conditions such as Lou Gehrig's disease, multiplesclerosis and even schizophrenia.

Our study shows that HERV genes are present in healthy tissues. The presence of HERVRNA may not be enough to connect the virus to a disease.

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It means that HERV genes are no longer good targets for drugs. There are a number of potential drugs that target HERVs. The activity of HERV genes in healthy tissue will need to be taken into account in the treatment of HERV genes.

Our research shows that HERVs may be beneficial to people. syncytin is a HERV that is derived from an ancient retroviruses and plays an important role in the birth of the placenta. All mammals depend on the virus-derived proteins in this genes to have a baby.

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The mice, cats, and sheep found a way to protect themselves from the original ancient virus that created them. If the host encounters the embedded viral genes, they will cause enough damage in the body to interfere with the replication of their ancestral virus. Scientists theorize that one HERV may have been involved in this protective role. A few more HERVs could have been co-opted by the human body in the past.

Unknowns remain

There is a level of HERV activity in the human body that was previously unknown.

There is still a lot of information to be learned about the ancient viruses that linger in the human genome. It's important to see if any of these genes are made into something.

Answering these questions will help researchers understand how the human body reacts to evolution and the ancient viral genes.

The conversation published this article. The original article is worth a read.

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