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TACF is no longer supporting development of D58 American chestnut trees

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Re: TACF is no longer supporting development of D58 American chestnut trees

#41

Post by jszymborski »

hedora wrote: post #40
tamcap wrote: post #33

Earlier quoted context omitted.

It's possible they checked before (and the article suggests they had an inclination where the gene should be) but the resultant backcrosses involved a spontaneous recombination of the relevant fragment. It's possible someone checked the wrong vial in lab, or mislabeled results. It's possible something funny "just happened". Wet lab is hard, and everyone is chasing the eureka moment.

My reading of the article suggests they modified the genomes of multiple trees, and the “winners” that got into the field happened to have ancestors that had moved the target gene to a different chromosome. They’re simultaneously trying to make precision modifications to the genome and also trying to preserve hundreds of wild strains. If they succeed, the required technological advances will probably be broadly appli…

That was my understanding too:

"Upon further and additional independent investigation, scientists confirmed that the trees they had been researching were in fact *descendants of a different event in the Darling line* in which the OxO gene had been inserted into a coding region, causing a deletion in a known gene. "

emphasis my own

Re: TACF is no longer supporting development of D58 American chestnut trees

#42

Post by acomjean »

CuriousCosmic wrote: post #24
gwern wrote: post #21

That is disappointing, but I'm also a little curious - why did this go all the way to field trials if the gene insertion was completely screwed up, to the point of being on the wrong chromosome ? In November 2023, through molecular analyses performed by partners at the University of New England and University of Maine, TACF learned that the OxO gene of all Darling 58 trees was on a different chromosome than expected…

Well for comparison the sunflower has around 30% more base pairs in it's genome than the human genome, kentucky bluegrass has more than double, spruces have around 7x as many, pines have over 10x, but oak has less than a third. So it's kind of all over the place. Even relatively similar plant species within the same family can have massively different genome sizes. Chinese chestnuts have a comparatively small genome…

Plants are wierd.

“Polyploid organisms have more than two sets of homologous chromosomes. For example, humans have two sets of homologous chromosomes, meaning that a typical human will have 2 copies each of 23 different chromosomes, for a total of 46. Wheat on the other hand, while having only 7 distinct chromosomes, is considered a hexaploid and has 6 copies of each chromosome, for a total of 42.”

https://en.m.wikipedia.org/wiki/Plant_genetics

Re: TACF is no longer supporting development of D58 American chestnut trees

#43

Post by 7thaccount »

dzdt wrote: post #31

The headline here does not come from the original article and is misleading. The actual article title is "Darling D58". The closest subheading matching the title given here is "Why TACF is No Longer Supporting Development of D58 or Deregulation of the Darling Line." The American Chestnut Foundation is still most certainly pursuing its mission to reseed America with blight-resistant seeds. Just they've discovered that…

I saw a video on this recently. It's super sad that such a magnificent tree (along with the American Elm) have been completely destroyed. So much majesty gone.

Re: TACF is no longer supporting development of D58 American chestnut trees

#44

Post by PcChip »

7thaccount wrote: post #43
dzdt wrote: post #31

The headline here does not come from the original article and is misleading. The actual article title is "Darling D58". The closest subheading matching the title given here is "Why TACF is No Longer Supporting Development of D58 or Deregulation of the Darling Line." The American Chestnut Foundation is still most certainly pursuing its mission to reseed America with blight-resistant seeds. Just they've discovered that…

I saw a video on this recently. It's super sad that such a magnificent tree (along with the American Elm) have been completely destroyed. So much majesty gone.

It came up in my feed a few days ago too

Re: TACF is no longer supporting development of D58 American chestnut trees

#45

Post by stritafarm »

joecool1029 wrote: post #11
eYrKEC2 wrote: post #8

Earlier quoted context omitted.

I bought some of those seeds and I just thought I had a black thumb. I planted my surviving seedlings this fall, a month before frost, and I hope they will survive winter..

I live in blight region (NJ). We have American seedlings growing here for a few years now, but I don't have faith that inside the range they'll reach maturity. Our mature American Chestnut tree is well established enough that it dies back some every few decades and recovers. This year I got 50 or so chestnuts out of it. I ate a few, they are great and never seem to get the weevil that the Chinese trees we have do (ba…

I was searching for information on where the blight region is and isn't. Everything I found simply said it is "widespread in the USA."

I have quite a few acres and local contacts in my area that also grow trees. Feel free to reach out.

Re: TACF is no longer supporting development of D58 American chestnut trees

#47

Post by anonymouskimmer »

robwwilliams wrote: post #38
gwern wrote: post #21

That is disappointing, but I'm also a little curious - why did this go all the way to field trials if the gene insertion was completely screwed up, to the point of being on the wrong chromosome ? In November 2023, through molecular analyses performed by partners at the University of New England and University of Maine, TACF learned that the OxO gene of all Darling 58 trees was on a different chromosome than expected…

This was often NOT done in many transgenic experiments 20 to 30 years ago. In mice transgenic insertions and inadvertent disruption of genes near the transgene insertion are only occasionally disruptive. The reelin gene disruption is a good example. This work was started long before cheap whole genome sequencing. However, comments are right—it was never too hard to examine the flanking sequence around the insertion s…

> There are not that many.

Ballpark how many is not that many?

Re: TACF is no longer supporting development of D58 American chestnut trees

#48

Post by whyenot »

The is a chestnut orchard in the Santa Cruz Mountains (SF Bay Area) that has American chestnut trees in it (also European, and at least one Asian chestnut). It’s kind of neat because you can compare the chestnuts from the different species. American chestnut has the smallest nuts of the three, but they are the sweetest and most flavorful.

Re: TACF is no longer supporting development of D58 American chestnut trees

#49

Post by joecool1029 »

redavni wrote: post #23
joecool1029 wrote: post #16

Earlier quoted context omitted.

Tried to respond to this before maybe the site will let me now. There's a redwood that was thought to be extinct that thrives in east coast conditions of the US. The dawn redwood is a fast grower, and while being the smallest of the redwood species is still quite a large tree. It was discovered in a valley in China I guess back in the 40's, previously only known to the fossil record. We have one here planted in the 1…

Wow fascinating. Apparently it is a deciduous tree.

It is. Just finished dropping its leaves/needles for the winter. I've heard from a few arborists they've had people ask if their tree needed to be cut down thinking it was dead, only to be told that's just what it does in the fall (it drops later than most of the other trees). We couldn't ID the one by my old house when I was a kid (internet was still early, nothing like inaturalist). Thought it was a larch, which having seen the tree now makes sense. I have been wondering after the recent HN topic if it has similar fire resistance/recovery that the giant redwoods out west have, realize we don't really know how long it'll live in the here since all were brought in the past 80 years. When the landlord planted it he misjudged how big it would grow (seems to be a common theme with the ones I see growing around). Until we got cats these red squirrels would eat the seeds in the small cones it produces and chuck them at our roof.

Other than the squirrel issue I have that was resolved, the tree is a lovely tree and I have had many dreams of them and memories of sitting in the shade under them with my cat as a kid. It doesn't throw sap like a fir does and the branches are thinner and unlikely to cause major damage to a house if they do come down.

Re: TACF is no longer supporting development of D58 American chestnut trees

#50

Post by huytersd »

7thaccount wrote: post #43
dzdt wrote: post #31

The headline here does not come from the original article and is misleading. The actual article title is "Darling D58". The closest subheading matching the title given here is "Why TACF is No Longer Supporting Development of D58 or Deregulation of the Darling Line." The American Chestnut Foundation is still most certainly pursuing its mission to reseed America with blight-resistant seeds. Just they've discovered that…

I saw a video on this recently. It's super sad that such a magnificent tree (along with the American Elm) have been completely destroyed. So much majesty gone.

Green ash is currently under attack and will be gone within the decade.
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