Major turnaround as researchers disown their own GE tree

CSNN National Page > Major turnaround as researchers disown their own GE tree

In a stunning turnaround, key researchers have disowned their own genetically engineered tree.

The American Chestnut Foundation (TACF) is discontinuing its development of the genetically engineered (GE or genetically modified) American chestnut tree called “Darling 58”. The announcement comes as TACF revealed its findings that this GE tree does not work. It is not blight-tolerant as promised, and it is short and weak. It is, however, still under consideration for approval by the US government for release into the wild. Read and share today’s press release from CBAN.

TACF developed the GE tree Darling 58 with the State University of New York College of Environmental Science and Forestry (SUNY-ESF) and advocated for planting this GE tree in the wild to “restore” the American chestnut to the forests of eastern North America. TACF now says that it is “unsuitable as a restoration tree”.

TACF heavily promoted Darling 58 as a “revolutionary transgenic American chestnut tree with enhanced blight tolerance”. However, TACF now reports, “analysis indicated striking variability in Darling trees’ blight tolerance, significant losses in growth competitiveness, reduction in overall fitness including stunted growth, leaf browning and curling, and increased mortality.” TACF and SUNY-ESF promoted and pursued this GE tree long before adequate scientific findings could be reported. TACF irresponsibly hyped this genetically engineered tree without evidence that it worked and SUNY-ESF submitted a request for US government approval based on just a few years of outdoor field tests. Read the TACF press release “TACF Discontinues Development of Darling 58” from Dec 8th.

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Take action today. Demand that SUNY-ESF withdraw their request for government approval of this failed GE tree. Click here to send your instant letter.

In January 2020, SUNY-ESF submitted a request to the United States Department of Agriculture (USDA) for approval to release of this GE tree into the wild. This regulatory decision is still pending and SUNY-ESF says, “We are continuing to pursue approval from federal agencies and work with regulators, and reviews remain underway.”

GE Tree Fails

The American Chestnut Foundation (TACF) identified “significant performance limitations” with its GE tree Darling 58 and discovered a “significant identity error”. These research findings reflect known risks with genetic engineering.

The findings show great variability in the blight tolerance of the GE tree i.e. there is no reliable blight tolerance. The researchers do not know why but have two hypotheses. The hypotheses point to known complexities and uncertainties including that genetically engineered traits can fail over time (genes can be suppressed) and that disease resistance traits are likely highly complex and interactive, involving multiple genes and regulatory systems.

Genetic engineering may impact an organism in unexpected ways. A single gene may influence more than one characteristic in an organism. In this case, the insertion of the key OxO gene appears to hamper the growth of the tree, for reasons as yet unknown.

After seven years, scientists also accidentally discovered that researchers who were studying the performance of Darling 58 were not actually experimenting with Darling 58 as assumed but with a significantly different tree called Darling 54. The mistake was only discovered once the science had progressed to make this testing more accessible. It tells us that the research undertaken on Darling 58 was premature because it was not sufficiently supported by the necessary information, technologies, and methodologies. This discovery also exposes the predictable role of human error in environmental risk (in this case, a “mix-up of pollen”).

While the research used the wrong GE tree, it was a GE tree that still provides useful insights into possible explanations for the “significant performance limitations” of Darling 58. The two trees share at least one common element that may be the cause of the performance failures.

Of note, Darling 54 is distinguished from Darling 58 because the key OxO transgene is located on a different chromosome. This is significant because the OxO gene of Darling 54 had been inserted into a coding region, causing an unwanted deletion (of 1069 base pairs) in a salinity tolerance gene (SAL1).

TACF says that “based on lessons learned through the process of researching and testing Darling lines of trees” it has created some new guiding principles for science and restoration efforts including, “Rigorous testing for efficacy throughout the life cycle of the tree life cycle (both in the lab and greenhouse, and in the field) prior to regulatory submission.”

You can read more of the details and our preliminary analysis in our new document “GE American Chestnut Performance Failures“.

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