Prof. Moshe Feldman from the Weizmann Institute investigates the secret of wheat's survival - the story of a study involving three generations of researchers
From right to left: Prof. Moshe Feldman, Prof. Avi Levy, and research student Khalil Kashkosh. The bread fields
Three Israelis of different generations, from different backgrounds, all captivated by the charms of wheat. The former kibbutznik, the immigrant from France and the Israeli Arab, all three wanted to be agronomists - each and his reason with his people - and all were fascinated by the secrets of the hardy plant that played a decisive role in the development of Western human culture.
As a member of Kibbutz Mishmar David in the 50s, Prof. Moshe Feldman spent many days sowing and then harvesting the crops in the wide (4,000 dunam) fields of the kibbutz. From his childhood he loved nature: "Agronomy was my natural choice", he says. But after a year of studying in Jerusalem, he was drawn to biology and evolution, and continued his studies in these fields. After completing his post-doctoral work, during which he worked with the well-known wheat researcher Ernest Sears, Feldman arrived at the Weizmann Institute of Science, and here he continued to decipher the basis of wheat's survival: it spread around the world, whether in the tropical regions of Brazil, dry areas in Sudan or the snowy prairies of Canada . "Wheat laid the foundation for the human culture we know today," says Feldman. "When people learned to grow wheat, their way of life changed - they were able to settle in certain places for a long time and built villages and towns. The wild wheat variety that humans inhabit - called the 'mother of wheat' - was discovered in Israel by Aharon Aharonson, and it still grows in this area."
About ten years after Prof. Feldman began researching wheat at the Weizmann Institute of Science, a new research student named Avi Levy arrived at the institute, today he is also a professor in the department of plant sciences at the institute. Levy immigrated from France at the age of 17 to fully realize the Zionist dream - to work in agriculture in the Land of Israel. "My mother cried when she heard that I decided not to be a doctor," he says. He also began studying agriculture, but his heart was captivated by the magic of wheat genetics. "Wheat is a small, beautiful and modest plant, with very few needs," says Levy, "but its genetics are very complex." He began his doctoral studies at the institute
Weizmann under the direction of Feldman, who had already acquired a reputation as a world expert on the genetics and evolution of wheat. In his post-doctoral work at Stanford University, he continued to be interested in cereals, and especially in corn, where he studied mobile genes that affect the stability of the genome, and in this way, its accelerated evolution. He then returned to the institute as an independent researcher. "At this point I had to prove that I wasn't just continuing the work of Musik (Prof. Feldman's nickname)," he says jokingly. Therefore he continued in a new research direction: the dynamics of the genome in other plants. "Fortunately, over time it became clear that my research has major implications for wheat research," he says. Thus the door to the study of his favorite organism was opened again.
About four years ago, another passionate fan joined the ranks of wheat lovers - research student Khalil Kashkoosh. "When I was born, the first things I saw were strawberries, flowers and wheat," he says, referring to the agricultural crops his father grew in the Arab village of Kalansawa in the Triangle. The dependence of the crops on water made the boy Khalil dream of developing a wheat variety that did not need large amounts of water. In order to realize the dream, he decided to become an agronomist. His studies left him all the time
Feeling that he doesn't know enough. This is how the dream of agronomy was pushed aside, in favor of studying for a PhD in plant sciences. "Like Prof. Levy's mother, my mother also wanted me to be a doctor. Now she consoles herself that I will have a doctorate, which, as she said, is 'good enough,'" he laughs. Kashkosh's research, guided by Feldman and Levy, has already produced three articles in prestigious scientific journals and won the prestigious Kennedy Award from the Institute's Feinberg Lectureship. "Khalil has a strong spirit and courage to do things that others before him have not done," says Feldman. "We have no doubt that his scientific future is very promising. He continues for a post-doctorate in a leading laboratory in the field, and from here, the sky is the limit." Looking from the side, it seems that Prof. Feldman, being an inspired teacher, laid the foundations for a dynasty of wheat scientists at the Weizmann Institute of Science.
Wheat may contain clues to one of the most mysterious questions in evolution: Did a primitive creature duplicate the genome of 500 million years ago, thereby creating the genetic jump that led to the formation of mammals? This question arises in light of the fact that wheat has doubled its genome several times in the past, thereby creating new species of wheat almost overnight. "When it comes to wheat," says Prof. Levy, "you can easily cause genetic multiplication in the laboratory. Therefore it is used as a unique genetic model. Thus, the study of wheat can lead to new insights into the evolution of other organisms, including humans."
For many years genetic duplication was considered a phenomenon that occurs mainly in plants, but today it is recognized as a driving force that influenced the evolution of the animal, plant and fungal kingdoms alike. Thus, for example, it turns out that many duplicated regions in the human genome were created about 500 million years ago, which points to the possibility that a genomic duplication event took place at that time. However, one should be careful in drawing quick conclusions in this area. As we know, genes change over time, and what started as a precise duplication of genes can change over millions of years. Nevertheless, the study of wheat may be used as a tool to examine the possibility that such an event, of genome duplication, did indeed play an important role in human evolution.
The institute's scientists who studied events of genome duplication revealed several events that occur after such duplication. They showed that, following genetic duplication, a "genetic shock" occurs, a situation in which dormant genes are awakened and other genes are silenced. An example of genes that arose in this process are genes that change their position on the sequence of the genome while skipping over other genes, therefore they are called "jumping genes". What was not known is that the jumping genes have more subtle means by which they sow confusion in the genome. The institute's scientists discovered that even when these genes do not jump, they can turn on or off nearby genes, thereby changing their control. These findings were recently published in the scientific journal Nature Genetics. Quite a few scientists believe that this phenomenon, discovered by the institute's scientists, may also occur
In human cells that also contain jumping genes. The wheat genome as we know it today is actually a mixture of several wheat species, whose genomes can serve as backup systems for each other. These backup copies come into play when the active genes undergo a mutation that disrupts their ability to function properly. It is possible that this phenomenon alludes to processes that took place in the very distant past, in one of the primitive creatures that can be considered our ancestors. If and when such a creature duplicated its genome, the redundant copies of the genes created, or the "backup systems", could serve as a basis for the creation and development of new functional abilities. Prof. Feldman: "The sudden increase in genetic material, together with tolerance to mutations, could have led to the formation of new genes, to increased genetic complexity, and over time to the development of more complex species."
Pop up gardens
Jumping genes are genes that are able to change their position on the genome sequence. More than fifty years ago they were discovered in corn by Barbara McClintock, who won the Nobel Prize for this discovery. Today it is known that jumping genes are common throughout the animal world: they make up about 40% of the human genome, and in plants they make up to 80% of all the genetic material, DNA. It is also known that the jumping genes play an important role in evolution. The mobility of the jumping genes may cause chaos in the genome due to the mutations they generate in other genes they jump on. Fortunately, most of the time the pop-up genes are dormant. Prof. Avi Levy, Prof. Moshe Feldman and PhD student Khalil Kashkosh from the Weizmann Institute of Science, showed in an article recently published in the scientific journal "Nature Genetics" that these genes have less blatant ways of causing confusion in the genome: even when they don't jump, they are able to turn off Or activate neighboring genes and decide for them when they will function. This takeover of genes may occur under certain pressures, including in hybrid productions, which are created as a result of fertilization between closely related species.
