Lynn Margulis: biography of this researcher and reference in Biology

When we think of renowned biologists, the first that comes to mind in all cases is a man with a serious face and bushy beard: Charles Darwin. It is not for less, because this highly influential scientist postulated the theory of natural selection, widely accepted and, although nuanced, irrefutable today. 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 the populations of beings alive.

If we move to the field of genetics, we may think of Gregor Mendel, that Augustinian friar who, with some peas and an unusual mind, he postulated Mendel's laws on which the foundations of heredity are still based today genetics. Without abandoning the genome, Watson and Crick, discoverers of the DNA double helix, not without multiple social controversies that we still have today.

These are some of the most recognizable names in the world of biology: as you will see, almost all of them are men who lived in past eras, but there are thousands of other equally important examples, despite having remained in the shadows of culture popular. This is the case of Lynn Margulis, a renowned biologist, scientist and disseminator, 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.

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Brief biography of Lynn Margulis

Lynn Margulis was born on March 3, 1938, in Chicago, United States. Since she was young, she already showed hints 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 she later went to the University of Wisconsin to (now) study biology. In the year 1960, she obtained a master's degree in genetics and zoology.

Her first publication as a "novice scientist" was devised in conjunction with her mentor, Walter Pault, which was published in 1958, in the professional journal Journal of protozoology. In it she addressed genetic issues in gender Euglena, small flagellated unicellular protists.

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

Once a Ph.D., Lynn Margulis She joined the Boston University faculty in 1966, where she taught biology for 22 years.. After her work as a teacher, she received the titles of "distinguished professor in botany" and "distinguished professor in biology" in 1988 and 1993, respectively. She moved to the geosciences department in 1997, where she held her honorary position until she died of a stroke in 2011.

Thought 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, since we see much more interest in reflecting the importance of her work and thought. We all have a personal life, but this does not usually define the ideological imprint that we leave in the common culture.

For most of her career as a scientist, Margulis was branded by her colleagues as an "extremist", because she did not agree with the Neo-Darwinian ideas that, for the most part, base the evolutionary mechanisms of the "survival of the most strong". In her own words: "Natural selection eliminates and maybe maintains, but it does n't create."

Margulis was a staunch defender of symbiosis as an evolutionary engine, that 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, be it good (usual symbiosis), indifferent for one of the parties (commensalism) or deleterious for the host (parasitism).

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Margulis and the endosymbiotic theory

Based on these premises, Margulis postulated the endosymbiotic theory or serial endosymbiosis in various articles, publications and scientific books, such as the following: On the origin of mitosing cells (1967), Origins of Eukaryotic Cells (1975) and Symbiosis in Cell Evolution (1981). In these documents, this eminence defended that the passage from the prokaryotic cell to the 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., that is, bacteria and archaea. The similarities are obvious, but we present some of the most striking in the following list:

• The mitochondria They are 1 micrometer in diameter and 8 µm in length. Some bacterial types can reach up to 10 µm, so it is not unreasonable to equate both sizes.
• The DNA of mitochondria and bacteria is extremely similar. The genetic information of both is stored, in general, 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.
• The ribosomes of bacteria are known as 70s, that is, they are smaller than those present in eukaryotic cells. The same happens in mitochondria and chloroplasts.

As you can see, the similarities are inescapable, and we haven't even covered them all. In any case, it should be noted that No matter how much apparent autonomy the mitochondria present, most of the proteins that they need to carry out their functions come from the ribosomes of the cytosol., that is, of the host cell.

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

All of this is to say that, despite the clear benefits for potential mitochondrial primordia, These bacteria have had to reject a large part of their autonomy throughout evolution in order to adapt excellently to their host: the eukaryotic cell.. Therefore, its genetic load is extremely low and most of the materials necessary for its permanence come from the cell cytosol.

In any case, this theory is widely accepted today and seems practically indisputable. With currently available genetic techniques, the genome of bacteria has been found to be phylogenetically associated with rickettsial proteobacteria, while chloroplasts show close similarities to cyanobacteriaNitrogen-fixing prokaryotic bacteria. The multiple evidences present today make Margulis endosymbiosis something 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 invested her life and expectations in leaving her legacy present in all future generations through obtaining knowledge.

Figures like this show us that, indeed, history is full of more than capable and skilled women. Unfortunately, normally their male counterparts still get all the credit, but as long as we continue writing and reading about these feminine eminences, the voice and presence of contemporary geniuses will continue among us. In the next section, we leave you some of her works, so you can learn from her first-hand.

Bibliographic 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 on the origin of species. Barcelona: Kairos.
• 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). A Revolution in Evolution (Vol. 20). University of Valencia.
• Margulis, L. (2012). Lynn Margulis: The life and legacy of a scientific rebel. Chelsea Green Publishing.