Navigation Links
How does inbreeding avoidance evolve in plants?

Inbreeding is generally deleterious, even in flowering plants. Since inbreeding raises the risk that bad copies of a gene will be expressed, inbred progeny suffer from reduced viability.

Many flowering plants are able to recognize and reject their own pollen, thereby preventing inbreeding despite the plants' hermaphroditic nature. This mechanism is a complex trait that involves the interaction of a gene that tags the pollen with an identifier molecule, and a gene that produces a molecule capable of detecting pollen produced by the same plant.

Evolutionary biologists have often argued that once complex traits are lost, they are seldom regained. But a new study, led by biologists at McGill University and published in the journal PLOS Biology, suggests that this may not be the case for self-pollen recognition.

In the evolutionary lineage leading to the genus Leavenworthia (a plant group related to canola and cole crops such as broccoli and cabbage), the ancestral genes that code for self-pollen recognition were lost. But the self-pollen recognition function in Leavenworthia appears to have been taken up by two other genes that originally may have had a different role -- for example, in pathogen recognition.

"Self-incompatibility," the pollen-recognition system that enables plants to avoid the inbreeding caused by self-pollination, involves a pair of tightly linked genes known as the S locus. In this study, the researchers analyzed the gene sequence, genome organization, and gene evolutionary history of S loci in members of the Brassicaceae family, which includes plants of the genus Leavenworthia.

"We conclude that both genes that comprise the ancestral S locus in the Brassicaceae were lost in Leavenworthia," says McGill researcher Sier-Ching Chantha, lead author of the study. Our analyses show, however, that plants of this genus have two other linked genes that exhibit patterns characteristic of an S locus. These genes occupy the same genomic position in Leavenworthia as do two non-S-locus genes in a related species. We suggest that these genes have evolved to assume the function of the pollen recognition system of self-incompatibility in Leavenworthia."

How plants avoid inbreeding, and the related topic of S locus evolution have been important research subjects for plant biologists. There can be hundreds of variants of a single S-locus in individual plant populationsa very unusual situation. In the animal world, a similar pheomenon is the many variations in immune-system genes. Immune system genes in animals, like the S locus in plants, are also involved in recognition, though in the case of immune genes it is foreign antigens rather than pollen types that are recognized. It seems that the recognition function can act in both systems to allow the evolution of large amounts of genetic diversity.

"Franois Jacob, the famous French biologist, once compared the action of natural selection to that of a tinkerer who uses the materials around him to produce a working object," notes McGill biology professor Daniel Schoen, the corresponding author of the study. "The evolution of the genes involved in self-pollen recognition in Leavenworthia provides a compelling example of this idea, and lends credence to the notion that the loss of complex traits may not always be irreversible."


Contact: Chris Chipello
McGill University

Related biology news :

1. Leading evolutionary scientist to discuss how genome of bacteria has evolved
2. Excessive worrying may have co-evolved with intelligence
3. Hitting snooze on the molecular clock: Rabies evolves slower in hibernating bats
4. As world warms, conservation evolves
5. Out of the mouths of primates, facial mechanics of human speech may have evolved
6. Giving ancient life another chance to evolve
7. Same adaptations evolve across different insects
8. Ion selectivity in neuronal signaling channels evolved twice in animals
9. Notre Dame researcher is shedding light on how jaws evolve
10. Menopause evolved to prevent competition between in-laws
11. A clearer picture of how assassin bugs evolved
Post Your Comments:
(Date:11/18/2015)... Nov. 18, 2015  As new scientific discoveries deepen ... and other healthcare providers face challenges in better using ... patients. In addition, as more children continue to survive ... adulthood and old age. John M. Maris, ... Hospital of Philadelphia (CHOP) . --> ...
(Date:11/17/2015)... , Nov. 17, 2015 Pressure BioSciences, Inc. ... the development and sale of broadly enabling, pressure cycling ... sciences industry, today announced it has received gross proceeds ... million Private Placement (the "Offering"), increasing the total amount ... or more additional closings are expected in the near ...
(Date:11/11/2015)... MedNet Solutions , an innovative SaaS-based eClinical technology company that ... announce that it will be a Sponsor of the ... held November 17-19 in Hamburg , Germany.  ... iMedNet , MedNet,s easy-to-use, proven and affordable eClinical ... able to deliver time and cost savings of up to ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015 /PRNewswire/ - Aeterna Zentaris ... that its business and prospects remain fundamentally strong ... Zoptrex™ (zoptarelin doxorubicin) recently received DSMB recommendation to ... completion following review of the final interim efficacy ... 2 Primary Endpoint in men with heavily pretreated ...
(Date:11/25/2015)... CA (PRWEB) , ... November 25, 2015 , ... ... genomics company uBiome, were featured on AngelList early in their initial angel funding ... an AngelList syndicate for individuals looking to make early stage investments in the ...
(Date:11/24/2015)... 2015 Halozyme Therapeutics, Inc. (NASDAQ: HALO ) will ... New York on Wednesday, December 2 at 9:30 a.m. ... and CEO, will provide a corporate overview. th ... at 1:00 p.m. ET/10:00 a.m. PT . Jim Mazzola ... a corporate overview. --> th Annual Oppenheimer Healthcare ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris ... of IIROC on behalf of the Toronto Stock Exchange, ... release there are no corporate developments that would cause ... --> --> About Aeterna ... . --> Aeterna Zentaris is a ...
Breaking Biology Technology: