Today I was forwarded this video on a study of a discovered effect of epigentic influence and TSD in Red Eared Sliders. I found it very interesting and of great value.
Here is the link to that short, 4 minute video:
Here is my response after watching it:
Now this is very interesting. Thank you for sharing this! This is great stuff for those of us working on TSD and especially when diapause is involved.
I immediately thought of the issues we have with TSD in G platynota and the way most babies artificially incubated turn out male despite high "female expected" temperatures. In studying diapause and TSD, I have had several conversations with my sister (one of the world's leading authorities on epigenetics) about possible epigenetic effects starting the cascade of events setting gender. I had always proposed that the way we diapause is affecting this. The Behler Center had good success in determining a pivot temperature and reliable sex outcomes of their G platynota. I noted that they used a diapause technique of just putting the eggs on a shelf in a room and let it fluctuate from high 60°s to high 70°s then incubate. This produced a definite and reliable pivot point for them. However, most breeders that were willing to share info, use a cooler diapause where they cool eggs from anywhere from 60° to 65° then incubate. Despite incubation at temps above the pivot point Behler Center found, most still turn out to be male.
In studying ground temps and weather data from Myanmar, I came to the conclusion that no natural nest in Myanmar would ever reach temperatures much below 70° in their winter. So I took the chance to change this trend and diapause my platynota eggs with warmer, fluctuating temps and not use the steady low temperature cooler method. I then incubated at temps most use of about 89°-90°. Of the holdback from my early 2019 clutches out of 7 I held back, 1 is male, 1 is yet undetermined and 6 are female.
Here we have remarks that the calcium channels as well as the proteins involved for epigenetic effects are both affected by temps. With the lower temps of diapause, I'll bet the calcium is not being utilized as noted in the higher temps for red ears since the diapause is so low. The same may be true for the protein STAT3 which would not able to be phosphorylated at these lower temps in diapause. As incubation begins the lack of this protein - pSTAT3, and possibly the lower calcium channel levels, would turn off the Kdm6b expression. Although not developing, the diapaused egg could certainly be establishing a chemical balance the later incubating temperatures cannot turn around, or turn around quick enough - and we have males developing, despite "female" incubation temperatures.
Mark
Here is the link to that short, 4 minute video:
Some like it hot…some don’t
A change in temperature can easily alter the course of our day. But for some reptiles and fish, it can set the course of their lives—deciding whether they emerge as male or female when they hatch. Basically, temperature affects whether the early gonad becomes a testis (making male hormones) or an...
www.researchsquare.com
Here is my response after watching it:
Now this is very interesting. Thank you for sharing this! This is great stuff for those of us working on TSD and especially when diapause is involved.
I immediately thought of the issues we have with TSD in G platynota and the way most babies artificially incubated turn out male despite high "female expected" temperatures. In studying diapause and TSD, I have had several conversations with my sister (one of the world's leading authorities on epigenetics) about possible epigenetic effects starting the cascade of events setting gender. I had always proposed that the way we diapause is affecting this. The Behler Center had good success in determining a pivot temperature and reliable sex outcomes of their G platynota. I noted that they used a diapause technique of just putting the eggs on a shelf in a room and let it fluctuate from high 60°s to high 70°s then incubate. This produced a definite and reliable pivot point for them. However, most breeders that were willing to share info, use a cooler diapause where they cool eggs from anywhere from 60° to 65° then incubate. Despite incubation at temps above the pivot point Behler Center found, most still turn out to be male.
In studying ground temps and weather data from Myanmar, I came to the conclusion that no natural nest in Myanmar would ever reach temperatures much below 70° in their winter. So I took the chance to change this trend and diapause my platynota eggs with warmer, fluctuating temps and not use the steady low temperature cooler method. I then incubated at temps most use of about 89°-90°. Of the holdback from my early 2019 clutches out of 7 I held back, 1 is male, 1 is yet undetermined and 6 are female.
Here we have remarks that the calcium channels as well as the proteins involved for epigenetic effects are both affected by temps. With the lower temps of diapause, I'll bet the calcium is not being utilized as noted in the higher temps for red ears since the diapause is so low. The same may be true for the protein STAT3 which would not able to be phosphorylated at these lower temps in diapause. As incubation begins the lack of this protein - pSTAT3, and possibly the lower calcium channel levels, would turn off the Kdm6b expression. Although not developing, the diapaused egg could certainly be establishing a chemical balance the later incubating temperatures cannot turn around, or turn around quick enough - and we have males developing, despite "female" incubation temperatures.
Mark