The mystery of our 145 foreign genes

07. 04. 2018
6th international conference of exopolitics, history and spirituality

Scientists have discovered parts of human DNA that do not come from our ancestors - this discovery could to change our view of evolution as such. The study questions the view that evolution can only occur on the basis of inherited genes. So did we get these foreign genes from microorganisms?

Scientists believe that we obtained these important foreign genes from microorganisms with which our ancient ancestors came into close contact. The study challenges the widely held view that the evolution of animals and humans relies solely on genes inherited from lineages. Scientists say evolution is still ongoing as such.

The main point of the research, which was published in Genome Biology, an open access journal, is Horizontal Gene Transfer (HGT), gene transfer between organisms living in the same environment. "This is the first study to show how horizontal gene transfer is extended to animals and humans and is a direct source of tens to hundreds of active foreign genes, "Stated the main author of the study, Alastair Crisp from Cambridge University. "Surprisingly, this is not an isolated phenomenon, it appears that horizontal gene transfer has contributed to the evolution of many, perhaps even all, animal species, and that this process continues. This means that we will have to reconsider our view of evolution as such."

HGT and its role

HGT plays an important role in the development of unicellular organisms and is probably the reason why it is possible that bacteria are able to develop antibiotic resistance so quickly. HGT probably also plays a key role in the evolution of some animals, such as nematodes, which have obtained parts of their genetic information from microorganisms and plants. Other creatures known to have HGT are some beetle species. Bacterial genes have been discovered in them, important for the production of enzymes, thanks to which they can digest, for example, coffee berries. However, the view that HGT could be part of the evolution of more complex animals or even humans has been frequently discussed and challenged in the past.

Horizontal Gene Transfer (HGT)

A process in which one organism receives genetic material (DNA) of another individual, although not his descendant. This process is widespread in single-celled organisms and is also the reason why bacteria can acquire antibiotic resistance so quickly. HGT probably also plays a key role in the evolution of some animals, such as nematodes, which have obtained some of their genetic information from microorganisms and plants, as well as beetles that have acquired bacterial genes.

The subject of the research was genomes of 12 species of Octomille, 4 species of nematodes and 10 species of primates, including humans. The researchers compared genes of one species with similar genes of another to see how different they really are. By comparing them with a different group of animal species, the researchers were able to estimate how long ago these genes were most likely to be passed on.

Research has shown that vertebrates have adopted a large number of genes, such as the ABO blood group gene, thanks to HGT. Most of the other adopted genes were related to enzymes that are part of metabolism. In humans, 17 previously reported adopted genes were confirmed and another 128 were identified that were not yet known. Some of these genes are involved in lipid metabolism, including fatty acid breakdown and glycolipid formation. Others are important components of the immune and inflammatory response, immune signaling of cells, antimicrobial response, amino acid metabolism, protein modification and antioxidant activity.

HGT plays an important role in the evolution of nematodes

HGT plays an important role in the evolution of nematodes

The team was able to identify the probable classes of organisms from which the transmitted genes originated. The most common source is bacteria and protozoa, for example viruses responsible for 50 foreign genes in primates. Some genes have been found to be derived from fungi. This may be one of the reasons why some previous studies, which only focused on bacterial HGT, have so resolutely rejected the notion that these human genes are derived from a foreign source. It was found that most of the HGT in primates took place a long time ago, the transfer probably occurred sometime in the period between the common ancestor of chordates and the common ancestor of primates.

The authors of the study argue that their analysis probably underestimates the true extent of HGT in animals, and that direct HGT between complex multicellular organisms is a real fact and is already known in some host-parasitic relationships.

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