DNA not always passed on from one parent to another through reproduction. In some cases, genetic material can pass from one organism to another through a process called horizontal genome transfer. For example, if you transplant two separate plants together, it is possible for DNA to be mix and exchanged for this individual survival.
Although this process has slowly understood for centuries, scientists have not always been sure how the whole genome travels from another cell. In a recent study published in the journal Science Advances last month, scientists at the Max Planck Institute of Molecular Plant Physiology in Potsdam say they have found a way for plants to mutate their entire genomes by transmitting horizontal genes.
Unusually, the process involves changes in the cell wall, after which the genetic transfer occurs by the cells transporting the whole organelles to neighboring cells. The organelles in question are plastids, a group of tiny organelles that contain chloroplasts, the “engine” of plant cells responsible for photosynthesis. Like mitochondria found in eukaryotic cells, chloroplasts also contain genetic material.
For this new study, the researchers used live-imaging of cells to show how a gene for antibiotic resistance could pass through cell-to-cell travel in the smallest distinct form of plastid between two grafted tobacco plants. Dr Alexander Hertle said in a statement, “We have been able to observe that the genome migration from cell to cell with high frequency occurs on both sides at this site.”
“The cell walls form a protrusion by forming a junction between two partners. The size of the pores created by them allows the entire plastid to move. Therefore, the genome does not move freely, but from cell to cell,” Dr. Hertle said. The choice of gene for antibiotic resistance was no coincidence; Horizontal gene transfer thought to be one of the main drivers of antibiotic resistance.
However, this process of horizontal gene transfer does not occur only in plant-and-plant or bacteria-or-bacteria. Scientists have documented a whole range where the peer-to-peer gene switches between different branches of life. A 2015 study found that the genomes of dozens of animals (including primates, worms and insects) all taken from bacteria and fungi by horizontal gene transfer. Even today, surprisingly, scientists have previously estimated that more than 100 of our genes were “stolen” from other organisms, such as bacteria or viruses, by transmitting horizontal genes.
Although there are plenty of bizarre examples of this process, it is uncertain how cell-to-cell travel of whole organelles (a process is seen in new research) occurs in life forms other than grafted tobacco plants. Nevertheless, the study sheds some light on a process that had a profound effect on the story of life on Earth.