Lynn Margulis: biography of this researcher and reference in biology.

A review of the life of Lynn Margulis, one of the most influential biologists in history.

When we think of renowned biologists, the first one that comes to mind in all cases is a man with a serious countenance and a bushy beard: Charles Darwin. No wonder, because this influential scientist postulated the theory of natural selection, which is widely accepted and, although nuanced, irrefutable to this day. Thanks to him, we know that in nature the survival of the fittest prevails, and that the impositions of the environment favor the appearance and discarding of certain characters in populations of living beings.

If we move to the field of genetics, we may think of Gregor Mendel, that Augustinian friar who, with a few peas and an unusual mind, postulated Mendel's laws on which the bases of genetic inheritance are still based today. Without leaving the genome, Watson and Crick, discoverers of the DNA double helix, may also come to mind, not without many social controversies that are still present today.

These are some of the most recognized names in the world of biology: as you will see, almost all of them are men who lived in the past, but there are thousands of other equally important examples, despite having remained in the shadows of popular culture. This is the case of Lynn Margulis, a renowned biologist, scientist and popularizer, who lived with us until 2011. If you want to know everything about her, keep reading, because here you will find a biography of Lynn Margulis.

Short biography of Lynn Margulis

Lynn Margulis was born on March 3, 1938, in Chicago, United States. From a young age she already showed signs of genius, as she graduated with honors from the University of Chicago in 1957, where she was accepted at the age of 15. Curiously, the first career that this scientist studied was Liberal Arts, although later she went to the University of Wisconsin to study biology.. In 1960, she obtained a master's degree in genetics and zoology.

Her first publication as a "junior scientist" was co-authored with her mentor, Walter Pault, and appeared in 1958 in the Journal of Protozoology. In it she addressed genetic issues in the genus Euglenaa small, flagellated, unicellular protists.

After finishing his master's degree in 1960, Margulis moved to the University of California (Berkeley) to study and obtain a doctorate specializing in genetics.. The thesis she defended that awarded her the position of doctor followed the line of research she began in her master's degree, as it was titled. An Unusual Pattern of Thymidine Incorporation in Euglenain which she explored the same genus of microorganisms mentioned above. Her doctoral work was completed at Brandeis University (Massachusetts) in 1965, where she obtained her first research position.

Once she received her doctorate, Lynn Margulis joined the teaching staff at Boston University in 1966, where she taught biology as a professor for 22 years.. Following her teaching tenure, she received the titles "Distinguished Professor of Botany" and "Distinguished Professor of Biology" in 1988 and 1993, respectively. He moved to the geosciences department in the year 1997, where he remained in his honorary position until he died of a stroke in the year 2011.

Thoughts and currents

Lynn Margulis married Carl Sagan, had two children, and divorced to remarry Thomas N. Margulis, a crystallographer. We do not need to know too much about the personal life of this eminence, as we see much more interest in reflecting on the importance of his work and thought. We all have a personal life, but it does not usually define the ideological imprint we leave on the common culture.

For most of her career as a scientist, Margulis was labeled by her peers as an "extremist", as she did not agree at all with the neo-Darwinian ideas that, for the most part, base evolutionary mechanisms on "survival of the fittest".. In his own words: "Natural selection eliminates and maybe maintains, but it doesn't create".

Margulis was a staunch defender of symbiosis as an evolutionary engine, i.e., that the association of different organismsthat is, that the association of different organisms (whether favorable or deleterious) is the most important cause of change and adaptation in nature. In these terms, we coin the term "symbiosis" as any relationship between two or more living beings, whether it is good (symbiosis in use), indifferent to one of the parties (commensalism) or deleterious to the host (parasitism).

Margulis and the endosymbiotic theory.

Based on these premises, Margulis postulated the endosymbiotic theory or endosymbiosis serialized in various scientific articles, publications and books, such as the following: On the origin of mitosing cells (1967), Origins of Eukaryotic Cells (1975) y Symbiosis in Cell Evolution (1981). In these papers, this eminence defended that the passage from prokaryotic cell to eukaryotic cell occurred through the symbiogenetic incorporation of certain bacteria.

Not without reason, Margulis compared the structure and functionality of mitochondria and chloroplasts (organelles present in the cytoplasm of eukaryotic cells) with the nature of prokaryotic cells, i.e. bacteria and archaea.The similarities are obvious, but we present some of the most striking ones in the following list:

• Mitochondria are 1 micrometer in diameter and 8 µm long. Some bacterial types can reach up to 10 µm, so it is not unreasonable to equate the two sizes.
• The DNA of mitochondria and bacteria is extremely similar. The genetic information of both is generally stored in a single circular chromosome without a nuclear membrane.
• These organelles are capable of synthesizing their own proteins to maintain themselves, just as prokaryotic microorganisms do.
• Bacterial ribosomes are known as 70s, i.e. they are smaller in size than those present in eukaryotic cells. The same is true for mitochondria and chloroplasts.

As you can see, the similarities are inescapable, and we have not even addressed them all. In any case, it is worth noting that, however much apparent autonomy the mitochondria present, most of the proteins they need to carry out their functions come from the ribosomes of the cytosol, i.e., from the cell of the cell.i.e., from the host cell.

If we go to investigate the bacterial genome, we will see that, for example, E. coli has about 4,000 different genes. On the other hand, the mitochondrial genome has been left with a paltry 37 coding genes, compared to the 25,000 present in the nucleus of human cells.

All this means that, despite the clear benefits for potential mitochondrial primordia, these bacteria have had to reject a large number of coding genes, these bacteria have had to reject much of their autonomy during the course of evolution in order to adapt excellently to their host: the eukaryotic cell.. As a result, their genetic load is extremely low and most of the materials necessary for their permanence come from the cell cytosol.

However, this theory is now widely accepted and seems virtually uncontested. With the genetic techniques available today, the bacterial genome has been found to be phylogenetically associated with rickettsial proteobacteria, while chloroplasts show close similarities with cyanobacteria, prokaryotic nitrogen-fixing bacteria.prokaryotic nitrogen-fixing bacteria. The multiple evidences present today make Margulis' endosymbiosis as accepted as natural selection itself in the scientific community.

Summary

Despite the foundation of the endosymbiotic theory, Margulis also stood out for many other things, such as her devotion to teaching, especially in the most disadvantaged regions. She was an excellent teacher, who poured her life and expectations into leaving her legacy present in all generations to come through the acquisition of knowledge.

Figures like this one show us that, indeed, history is full of more than capable and skillful women. Unfortunately, usually their male counterparts continue to take all the credit, but as long as we continue to write and read about these female eminences, the voice and presence of contemporary geniuses will continue among us. In the following section, we leave you with some of her works, so you can learn from her firsthand.

Bibliographical references:

• Lovelock, J. E., & Margulis, L. (1974). Atmospheric homeostasis by and for the biosphere: the Gaia hypothesis. Tellus, 26(1-2), 2-10.
• Margulis, L., & Fester, R. (Eds.). (1991). Symbiosis as a source of evolutionary innovation: speciation and morphogenesis. Mit Press.
• Margulis, L., & Sagan, D. (2003). Capturing genomes: a theory of the origin of species. Barcelona: Kairós.
• Margulis, L. (1971). Symbiosis and evolution. Scientific American, 225(2), 48-61.
• Margulis, L. (1981). Symbiosis in cell evolution: Life and its environment on the early earth.
• Margulis, L. (1993). Symbiosis in cell evolution: microbial communities in the Archean and Proterozoic eons.
• Margulis, L. (1996). Archaeal-eubacterial mergers in the origin of Eukarya: phylogenetic classification of life. Proceedings of the national academy of sciences, 93(3), 1071-1076.
• Margulis, L. (2002). Una revolución en la evolución (Vol. 20). Universitat de València.
• Margulis, L. (2012). Lynn margulis: The life and legacy of a scientific rebel. Chelsea Green Publishing.