We celebrate the pioneering women in the study of DNA

Every February 11th, the International Day of Women and Girls in Science is celebrated to highlight women's contributions to scientific progress. This year, there is also another celebration: the 25th anniversary of the publication of the first draft of the human genome, based on the almost complete sequencing of all our chromosomes. This milestone—having our instruction manual—opened the door to understanding why humans are the way we are. Since then, enormous strides have been made, and articles will surely be published about the many important scientists who have contributed to this progress. But on the occasion of February 11th, we must also remember the pioneering women scientists who made significant contributions to laying the foundations of the DNA and genome era, beyond Rosalind Franz. Today, it is worth remembering two contemporary researchers, Martha Chase and Maxine Singer, both deceased, two very different faces of the difficult path women have taken in the world of science.

The Kitchen Mixer Experiment

The name of Martha Chase It will be indelibly linked to the experiment that definitively settled the controversial question of whether genetic material was DNA or proteins.Hershey and Chase experiment, or the kitchen mixer experiment It was carried out in 1952, before Watson and Crick determined the structure of DNA. Chase was the technician from Alfred Hershey's laboratory. Both researchers were working with bacteriophages, viruses that attack bacteria, since they are made up only of DNA and proteins, both molecules under discussion. Their ingenious experiment combined the separate radioactive labeling of these two types of molecules to identify which one penetrated the host and determined the formation of more viruses.

Since there wasn't much laboratory equipment at that time, the benchtop centrifuges used today didn't exist, and Chase came up with the idea of ​​using a kitchen blender—very similar models are still on the market today—to separate bacteria from viruses by centrifugation. Although previous work by other authors had been done, her results conclusively demonstrated that the genetic material of bacteriophages (and therefore of living beings) was DNA, and for this reason, Alfred Hershey, but not Martha Chase, received the Nobel Prize in Medicine in 1969. In a petty act, Hershey didn't even mention the name of his assistant and co-author during his acceptance speech, even though her contribution to the prize-winning research was undeniable. Chase was not yet a doctor at that time; in fact, she earned her doctorate years later in another laboratory, but her personal life was difficult and unhappy. She suffered bouts of depression due to the lack of recognition and the difficulties associated with being a woman in the world of research, which forced her to abandon science. Although young, she developed dementia prematurely and died of pneumonia, long forgotten. Nevertheless, her experiment continues to be explained in all genetics textbooks as the definitive experiment that ushered in the era of DNA.

The Geneticists' Bible

Another great scientist in the pre-human genome is Maxine SingerBorn and educated in Brooklyn public schools in the 1930s and 40s, she studied chemistry and biology, earning her doctorate on proteins. She chose to research the then-emerging world of DNA and RNA because she found it a fascinating intellectual challenge. She ended up participating in the elucidation of the genetic code universal to all living beings. Furthermore, she was a pioneer in the nascent field of genetic engineering, quickly recognizing the bioethical problems of using and potentially misusing techniques that allowed for changing or modifying the genetic instructions of living beings, creating new synthetic genes without knowing their long-term impact. This led her to co-organize the first conference on the bioethics of genetic applications in biotechnology in 1975 in Asilomar, California, before the first bioethics textbooks on clinical applications were published. We also owe to her and her group the identification and analysis of an essential component of the human genome: the mobile genetic elements LINE. These elements have shaped our genome and are a source of mutations and genetic variability. We have about 100,000 of them, and they make up around 20% of our genome (for reference, protein-coding genes only account for 2% of the genome). Singer's vast knowledge of the structure, composition, and function of the human genome was shared with hundreds of thousands of geneticists worldwide through the publication of a book that became the "bible" for all geneticists, "Genes and Genomes" (Maxine Singer and Paul Berg), just as the Human Genome Project was getting underway. Singer didn't realize the discrimination women face in the world of science until she achieved She was an independent researcher and found that no male students wanted to work with her. because they believed they couldn't advance in their scientific careers under a woman's leadership. This made her a fervent advocate and defender of women in science. Her undeniable scientific merit, communication skills, and compelling personality made her shine brightly, and unlike Chase, Singer received awards and recognition and participated in the political and scientific strategy of her country, the United States, holding various positions in Congress and other institutions. Furthermore, she was the mother of four children, an important fact because many female scientists must sacrifice their personal lives for science without abandoning scientific research. She is truly a role model for girls and other women.