[Coral-List] [Cnidarian-dinoflagellate-symbiosis] genetic connectivity of Symbiodinium individuals within a single colony

[Daniel Merselis]

Hello again,

One more possibility for option 1 (endogenous repopulation only):

What if the host gastrodermal cells containing the cryptic endosymbiont are
relatively well dispersed through the colony and divide rapidly following
bleaching and cryptic symbionts are distributed to daughter cells? A 0.01%
symbiont could reach 100% in a little over 13 cell divisions.

There's evidence for necrosis and apoptosis of gastrodermal cells during
bleaching itself- Is there evidence for massive turnover of gastrodermal
cells coinciding with bleaching recovery?

In corals with a bleached patch, is there a wave of new gastrodermal cells
moving in from the outside of the patch inwards or are gastrodermal cells
within the patch a similair age to those outside of the patch after
recovery?

Best,
Dan

sent from my phone.

On Fri, Mar 22, 2019, 11:22 AM Daniel Merselis <danielmerselis at gmail.com>
wrote:

> Hi everyone- Very interesting topic!!
>
> It seems that possibility #1 "endogenous only" is a hypotheses which can
> never be falsified, because doing so means destroying the entire colony.
>
> Under an "endogenous only" model, how do we explain cryptic symbionts
> spreading from the remote corner of a colony to eventually dominate it?
> Presumably this would require distribution by means of the gastrovascular
> space and independent phagocytosis events by gastrodermal cells elsewhere
> in the colony. This gastrodermal space is also a route of entry for
> seawater likely containing the occasional exogenous symbiont. How could the
> host gastrodermal cell have a mechanism of specificity that will allow the
> cryptic symbiont from some far corner of the host, but deny the exogenous
> symbiont? -here I'm not talking about specificity or favor a host may have
> for a particular species of symbiont, but how would the host know what's
> endogenous and what's exogenous even if of the same species?
>
> If not through independent phagocytosis, does the "endogenous only"
> hypothesis require a mechanism for symbiont passing from one gastrodermal
> cell to another without entering the gastrovascular cavity?
>
> What have I gotten wrong?
>
> Best,
> Dan
>
> Dan Merselis
> PhD candidate
> Rodriguez-Lanetty Lab
>
> On Fri, Mar 22, 2019 at 10:59 AM John Ware via Coral-List <
> coral-list at coral.aoml.noaa.gov> wrote:
>
>> Hello List, Misha, Andrew, et al (I always wonder: who is al?)
>>
>> Andrew states that "this same discussion has been playing out for at
>> least 18 year...".
>>
>> Looking at papers related to this issue of trading symbionts that have
>> come out over the past 10 yrs or so, I no longer see references to the
>> Adaptive Bleaching Hypothesis published by Bob Buddemeier and Daphne
>> Fautin in 1993 - so how about over 25 years!!
>>
>> John
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>>
>