Genome complexity: plant genes protect stem cells (Introduction)

by David Turell , Thursday, April 25, 2019, 19:02 (2038 days ago) @ David Turell

Backup mechanisms are necessary in nature:

https://www.sciencedaily.com/releases/2019/04/190415172156.htm

"In flowering plants, stem cells are critical for survival. Influenced by environmental factors, stem cells direct how and when a plant will grow. Whether a plant needs deep-reaching roots, taller stems, or more leaves and flowers, it is the stem cells that produce new cells for the job.

"That's also why having too many or too few stem cells can disrupt a plant's growth.

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"In a paper published in Nature Genetics, Lippman and CSHL Professor David Jackson describe the genetic mechanisms that ensure "a deeply conserved stem cell circuit" maintains some function, even if defects occur in a signaling protein called CLV3, and the receptor with which it interacts, CLV1.

"Those players are critical for ensuring a plant has the right number of stem cells throughout life, and we discovered there are backup systems that kick in when these players are compromised through chance mutations," explains Lippman.

"The researchers determined that although the stem cell circuits are essential for flowering plants, the genetic backup systems can vary drastically from plant to plant.

"If the gene producing CLV3 is disrupted by a mutation in a tomato, for instance, a related gene will stand in for it. However, Jackson's team discovered that in the case of maize, two genes are working in parallel to produce the essential signaling protein.

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"'We were surprised to see such big differences," says Jackson, "but in retrospect it reveals the power of evolution in finding novel ways to protect critical developmental circuits.'"

Comment: Not exactly the same type of convergence we usually see, but more evidence of an underlying program for evolution. An other evidence of design in that when the plant appeared in evolution, such protection was required and must have developed contemporaneously.