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Pond scum and the gene pool: One critical gene in green algae responsible for multicellular evolution, understanding of cancer origin

Date:
May 5, 2016
Source:
Kansas State University
Summary:
A single gene is responsible for the evolution of multicellular organisms, new research indicates. Scientists were looking for what caused single-celled organisms to evolve into multicellular organisms when they discovered the importance of a single gene, retinoblastoma, or RB. RB, known for being defective in cancer patients, is a critical gene necessary for multicellular life; previous theories have indicated that multiple genes might be responsible for multicellularity.
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A gene found in this eight-celled green algae is responsible for the evolution of multicellular organisms.
Credit: Kansas State University

Kansas State University biologists are skimming pond scum for clues of multicellular evolution and possible origin of cancer.

Brad Olson, assistant professor in the Division of Biology; Erik Hanschen, doctoral student at the University of Arizona; Hisayoshi Nozaki, University of Tokyo; and an international team of researchers found a single gene is responsible for the evolution of multicellular organisms. The study is published in a recent issue of Nature Communications.

Olson and Hanschen were looking for what caused single-celled organisms to evolve into multicellular organisms when they discovered the importance of a single gene, retinoblastoma, or RB. Olson and Hanschen found that RB, known for being defective in cancer patients, is a critical gene necessary for multicellular life. According to Olson, previous theories indicated that multiple genes might be responsible for multicellularity.

"Rather than the situation where hundreds of genes have to evolve simultaneously, it's a very subtle change in one gene that causes a reprograming of the cell cycle," Olson said. "Not only did we find a critical gene for multicellularity, it turns out it turns out to be a tumor suppressor and it is much easier to evolve multicellularity than anticipated."

Funded by the National Science Foundation and the National Institutes of Health, Olson, Hanschen and their colleagues compared genomes of multicellular alga called Gonium pectorale and its single-celled alga relative, Chlamydomonas reinhardtii. The RB gene is in both algae but has small differences in structure and how it regulates cell cycles.

"RB plays a fundamental role in cell multiplication by regulating cell cycles just before DNA replication starts," Olson said. "Cancer occurs when this gene is defective. In terms of cell cycle and cancer progression, think of RB like the brakes on your car. When the brakes are defective, there is no way to control how the vehicle stops."

Multicellularity has evolved dozens of times independently, according to the researchers.

"It is well-known that plants, animals and fungi evolved independently, but so did red, green and brown algae, volvocine algae, slime molds and bacteria; it's a process that has happened many, many times," Hanschen said. "The result we find with RB is intriguing because this pathway and this gene are shared among so many of these independent multicellular groups, which are separated by hundreds of millions of years."

When the researchers took the RB gene from Gonium and introduced it in to Chlamydomonas, it caused Chlamydomonas to become multicellular.

"Gonium is representative of the first steps toward the evolution of complex multicellular organisms such as plants and animals," Olson said. "These findings have the potential to help scientists understand the origin of cancer and may contribute to future abilities to treat and detect cancer."

Research contributors at Kansas State University include Tara Marriage, postdoctoral associate; Jaden Anderson, senior in biology, Overland Park; and Halle Sparks, junior in biology, St. Louis, Missouri. Additional collaborators include Richard Michod, University of Arizona; and Takashi Hamaji, University of Tokyo.

Olson first tested the RB gene in 2012 and then organized the entire research team to investigate numerous other theories for multicellular evolution.

"There have been so many hypothesis about how multicellular evolved," Olson said. "We went through and tested all those hypotheses. We wanted to make sure that our finding was the best."


Story Source:

Materials provided by Kansas State University. Note: Content may be edited for style and length.


Journal Reference:

  1. Erik R. Hanschen, Tara N. Marriage, Patrick J. Ferris, Takashi Hamaji, Atsushi Toyoda, Asao Fujiyama, Rafik Neme, Hideki Noguchi, Yohei Minakuchi, Masahiro Suzuki, Hiroko Kawai-Toyooka, David R. Smith, Halle Sparks, Jaden Anderson, Robert Bakarić, Victor Luria, Amir Karger, Marc W. Kirschner, Pierre M. Durand, Richard E. Michod, Hisayoshi Nozaki, Bradley J. S. C. Olson. The Gonium pectorale genome demonstrates co-option of cell cycle regulation during the evolution of multicellularity. Nature Communications, 2016; 7: 11370 DOI: 10.1038/ncomms11370

Cite This Page:

Kansas State University. "Pond scum and the gene pool: One critical gene in green algae responsible for multicellular evolution, understanding of cancer origin." ScienceDaily. ScienceDaily, 5 May 2016. <www.sciencedaily.com/releases/2016/05/160505105021.htm>.
Kansas State University. (2016, May 5). Pond scum and the gene pool: One critical gene in green algae responsible for multicellular evolution, understanding of cancer origin. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2016/05/160505105021.htm
Kansas State University. "Pond scum and the gene pool: One critical gene in green algae responsible for multicellular evolution, understanding of cancer origin." ScienceDaily. www.sciencedaily.com/releases/2016/05/160505105021.htm (accessed May 23, 2017).

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