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Scientist/professor seeks reptilian test subjects!
Only partially true...
Hi, I'm Jason!
I've been working with reptiles for significantly more than half of my life (25+ years), as a hobby, as a business, and in education (both at community and university levels). Now I am slowly beginning to integrate my hobbies into my research. (I'm a Microbiologist, for those who are curious... so not much natural overlap with reptiles)
Back in 2012 (during graduate school), I launched Sterling Serpents, my reptile breeding "business", named after my favorite ball python in my collection at the time, which happened to be a Sterling Bee (super pastel, spider, cinnamon). At that time, I had been breeding Ball Pythons for quite a few years, and had already begun branching out into other species, primarily Western Hognose Snakes (H. nasicus).
Since the early days of running Sterling Serpents, I've largely moved away from breeding Ball Pythons (though I do still have quite a few in my collection), and put a lot more emphasis on geckos.
Currently I'm primarily producing R. leachianus geckos, but also keep/breed Crested Geckos, Mourning Geckos (if you can call that breeding), and Uroplatus ebenaui (Spearpoint Leaf-Tailed Geckos).
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Now... more about those test subjects!
One of the questions that had arisen over the years of working with these animals has been surrounding sex determination and development in gecko species. As I'm sure most people here know, it's not always easy to determine if a gecko (depending on species) is a male or female until it approaches adulthood.. (Uroplatus geckos are an interesting example of a gecko that you CAN generally identify male/female at birth due to sexual dimorphism).
Some geckos (leopard geckos, many day geckos, etc.) have sexual development dictated by the temperature they incubate at.
Others (Malagasy Ground Geckos, Tokay geckos, etc.) have chromosomally encoded sex determination, and temperature has little impact on development).
Among the most interesting are the Mourning Geckos, which are predominantly female, and reproduce parthenogenically (self-reproducing without a male). How is sex determined in an animal that only has one sex (for reproductive purposes anyway)?? Or perhaps more precisely: How do Male mourning geckos develop if they are essentially genetically identical to their female progenitors?
Hopefully, with the help of the reptile community, we'll be able to find out! (keep your eyes peeled for male mourning geckos!)
I'd love to talk more about this research, and about any other reptile-related research with anyone interested! (this sex determination question is only the tip of the iceberg!)
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Looking forward to meeting folks here!
5 Replies
Jason W Arnold·
Note: Either Italics and Bold commands do the same thing in the text.. or I made a terrible mistake!
Also, there does not appear to be a way to edit text once published (which ultimately is probably fine/for the best, but will DEFINITELY stress me out!)
Jason W Arnold·
erie_herps wrote:
I've wondered this for a long time with mourning geckos. I've read that males are important for increasing genetic diversity, but in that case they should be producing more males. I look forward to seeing what you come up with.
That is generally the case with animals that share similar reproductive mechanisms (nematodes, etc.), however the male mourning geckos are sterile, and contribute nothing as far as genetic diversity to the community.
There are 3-4 different mechanisms that I can think of, and I DO have a primary hypothesis that I'm hoping to test... just need to find some males! (all the males I've found in the past few years have been overseas, making acquisition challenging!)
Hopefully I'll either find or hatch one soon!
Kathryn Brown·
Hi, I've been breeding Tokays for 15 years or so. They are temperature sex dependant. Lower temperature produces females and higher temperatures produce males. Over the years, I discovered this because almost all my babies are female. The only time I have produced males is when I incubate the eggs myself, when eggs are laid close to the heat source, or when the cage is in a room in the 80's or higher. Most of my cages are in rooms set to 75 degrees, hence all the female babies.
Jason W Arnold·
TheReptileWhisperer1 wrote:
Hi, I've been breeding Tokays for 15 years or so. They are temperature sex dependant. Lower temperature produces females and higher temperatures produce males. Over the years, I discovered this because almost all my babies are female. The only time I have produced males is when I incubate the eggs myself, when eggs are laid close to the heat source, or when the cage is in a room in the 80's or higher. Most of my cages are in rooms set to 75 degrees, hence all the female babies.
So I've noticed similar phenomenon in other species with chromosomally encoded sex determination, but it's very challenging to prove that it's not consequence.
It would be interesting to look at whether or not temperature early in embryonic development can actually result in changes at the genomic level, or if sex determination is less influenced by chromosomal presence, but by gene expression early in development.
According to most published literature I've been able to find, Tokays have chromosomally encoded sex determination, but I'm fairly confident that there is more going on in a lot of gecko species than we really know!
