First of all we have access to less than half of this organism only. What about root mutations?
And second, we have accces only to the 'bad half' in our search for mutations. Trees act in some ways as 'colonial organisms'. Each branch competes with other branches. Some can place itselves in a better place and trive, and other not. Is a well known fact by gardeners that mutated branches are outcompeted and die more often. Mutations in cells of flowers, leaves or fruit peduncles are simply auto-cleaned in winter, and some barks fall also.
Oaks are customed to having several of types of 'cancers' and react actively against, isolating the tissue or nurturing the tumor for a while before 'autopruning' it.
There is not need here of a genetic mechanism to protect cells from mutations. Such system may happen, but not necessarily.
Not all mutations have a phenotypic effect that can be selected against. The interesting part of this study is that there is (apparently) a lack of mutations in non-coding regions.
> First of all we have access to less than half of this organism only. What about root mutations?
The study specifically examined the issue of mutations arising in the cell line from zygote to terminal branches, since that is where reproduction takes place and we are most interested in mutations that are passed from one generation to the next. If stem cells at the root tips show more mutations, so what? The authors established (pending peer-review) a surprisingly low rate for this particular sequence, that's sufficiently interesting in itself.
> And second, we have accces only to the 'bad half' in our search for mutations...
"Sixteen of the 17 SNVs identified in the Napoleon Oak occurred in introns or non-coding sequences that are probably neutral... These results... demonstrate [the mutations'] gradual, nested appearance and fixation in developmentally connected branches during the growth of the oak tree. Thus, while the exact ontogeny of the Napoleon Oak may be difficult to reconstruct, our SNV analysis generated nested set of lineages supported by derived mutations"
They sampled across many independent cell lineages and across noncoding regions, and they are looking specifically at mutation rates in the cell line that leads to gamete formation. The kind of mutational "auto-cleaning" you describe is mostly just your unsubstantiated thinking about growth-related phenomena that are actually explained by a host of non-mutational factors; in any case undersampling due to rare deleterious mutation self-pruning would not have a confounding effect on the results here.
>There is not need here of a genetic mechanism to protect cells from mutations.
Just because trees can tolerate certain kinds of pathogen and insect-induced tumors doesn't mean they are entirely without need of protecting genome sequence integrity. Plants like other organisms do have sophisticated mechanisms to repair and maintain DNA, this becomes especially important in the stem cell lines leading to reproduction. The study shows these mechanisms in this oak are particularly efficient.
> If stem cells at the root tips show more mutations, so what?
So then, we couldn't say that oaks have a surprising absence of mutations. And we should remember that roots can work as part of the reproductive systems in this organisms. Could change our interpretation and point of view about results. The biggest trees in the world (heavier than Sequoias) are root clonal colonies.
> The kind of mutational "auto-cleaning" you describe is mostly just your unsubstantiated thinking about growth-related phenomena that are actually explained by a host of non-mutational factors;
I'm not sure that I'm understanding this. Specially the host of factors part. Could you please rephrase it?
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[ 0.19 ms ] story [ 15.5 ms ] threadFirst of all we have access to less than half of this organism only. What about root mutations?
And second, we have accces only to the 'bad half' in our search for mutations. Trees act in some ways as 'colonial organisms'. Each branch competes with other branches. Some can place itselves in a better place and trive, and other not. Is a well known fact by gardeners that mutated branches are outcompeted and die more often. Mutations in cells of flowers, leaves or fruit peduncles are simply auto-cleaned in winter, and some barks fall also.
Oaks are customed to having several of types of 'cancers' and react actively against, isolating the tissue or nurturing the tumor for a while before 'autopruning' it.
There is not need here of a genetic mechanism to protect cells from mutations. Such system may happen, but not necessarily.
The study specifically examined the issue of mutations arising in the cell line from zygote to terminal branches, since that is where reproduction takes place and we are most interested in mutations that are passed from one generation to the next. If stem cells at the root tips show more mutations, so what? The authors established (pending peer-review) a surprisingly low rate for this particular sequence, that's sufficiently interesting in itself.
> And second, we have accces only to the 'bad half' in our search for mutations...
"Sixteen of the 17 SNVs identified in the Napoleon Oak occurred in introns or non-coding sequences that are probably neutral... These results... demonstrate [the mutations'] gradual, nested appearance and fixation in developmentally connected branches during the growth of the oak tree. Thus, while the exact ontogeny of the Napoleon Oak may be difficult to reconstruct, our SNV analysis generated nested set of lineages supported by derived mutations"
They sampled across many independent cell lineages and across noncoding regions, and they are looking specifically at mutation rates in the cell line that leads to gamete formation. The kind of mutational "auto-cleaning" you describe is mostly just your unsubstantiated thinking about growth-related phenomena that are actually explained by a host of non-mutational factors; in any case undersampling due to rare deleterious mutation self-pruning would not have a confounding effect on the results here.
>There is not need here of a genetic mechanism to protect cells from mutations.
Just because trees can tolerate certain kinds of pathogen and insect-induced tumors doesn't mean they are entirely without need of protecting genome sequence integrity. Plants like other organisms do have sophisticated mechanisms to repair and maintain DNA, this becomes especially important in the stem cell lines leading to reproduction. The study shows these mechanisms in this oak are particularly efficient.
So then, we couldn't say that oaks have a surprising absence of mutations. And we should remember that roots can work as part of the reproductive systems in this organisms. Could change our interpretation and point of view about results. The biggest trees in the world (heavier than Sequoias) are root clonal colonies.
> The kind of mutational "auto-cleaning" you describe is mostly just your unsubstantiated thinking about growth-related phenomena that are actually explained by a host of non-mutational factors;
I'm not sure that I'm understanding this. Specially the host of factors part. Could you please rephrase it?