Following Ivan Wallin's early experimental work, the endosymbiotic hypothesis was largely ignored for $${}50$$ years because scientists were unaware that organelles contained their own DNA. However, the hypothesis was resurrected in the $${}1960$$s with the discovery of mitochondrial and chloroplast DNA.

Google

Based on the ability of chloroplasts to reproduce independently, Russian botanist Konstantin Mereschkowski ($${}1855$$–$${}1921$$) suggested in $${}1905$$ that chloroplasts may have originated from ancestral photosynthetic bacteria living symbiotically inside a eukaryotic cell. He proposed a similar origin for the nucleus of plant cells. This represented the first articulation of the endosymbiotic hypothesis to explain how eukaryotic cells evolved from ancestral bacteria.

Konstantin Mereschkowski

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

American anatomist Ivan Wallin ($${}1883$$–$${}1969$$) furthered the endosymbiotic hypothesis by experimentally testing the similarities between mitochondria, chloroplasts, and bacteria in the $${}1920$$s. He published several papers supporting the hypothesis, including a $${}1926$$ co-authored work with Konstantin Mereschkowski. Wallin claimed to culture mitochondria outside their host cells, but scientists dismissed this as bacterial contamination. Modern genome sequencing supports his critics, revealing that much of the mitochondrial genome transferred to the host cell's nucleus, preventing independent mitochondrial life.

Learn Before

Related