Reptile & Amphibian Forums

Just an interesting story thought you would all like to hear. I bread a 2001 NERD 100% Het Carmel male to 3 normal females. I got 3 clutches, 4,5 and 7 eggs. All hatched, all are females. I know I know, I sexed them wrong right? I popped and probed multiple times. I even had another breeder sex them and he came up with females as well. I went back to a clutch of 50% het pieds and used the 4.1 as a control.

No matter how you slice it, I got all females. I was hoping for 4 or 5 to continue my Carmel project. Doesnt get much better than that.

Has anyone else had this happen before? I wasnt going to breed that male this year, but now I feel like I have to. What if he gives all females again? He would definitely up his own worth for sure.

Tom Siegrist
Siegrist Reptiles
727-505-4676

0.0015%

The odds that any 16 eggs turn out to be all one sex.

If they were all from one female, I would wonder if it had something to do with her (parthenogenisis, maybe). Cant think of a biological explanation for a male to produce only female offspring...must just be crazy dumb luck.

I guess it could be possible that this male does not produce many functional or viable "y" sperm. From what I understand, there are cases where males of other species consistantly produce "y" sperm that are immobile or deformed and their resulting offspring are predominatly female. Don't see why it can't happen in ball pythons. Or then again, it could be a very lucky occuarnce.

W. Smith

I may be wrong - but I think somewhere I read that in balls - it was the females genetic input that that determined which sex the offspring are.
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Tosha

"Nihil facimus sed id bene facimus"

6.34.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Anakin Skywalker)
0.0.1 Green Tree Python (Verdi)
0.1.0 Bredls Python (Smurfette)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Desert Tortoise (Pope John Paul aka JP )
2.2.1 Fish (1,2,3,4)
0.0.0 frogs rescued from pool skimmer
0.0.1 Lizards of unknown origin

>>I may be wrong - but I think somewhere I read that in balls - it was the females genetic input that that determined which sex the offspring are.
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>>Tosha
>>
>>"Nihil facimus sed id bene facimus"
>>
>>
>>
>>6.34.0 Ball Python (Harry and Fluffy and gang)
>>1.0.0 Angolan Python (Anakin Skywalker)
>>0.0.1 Green Tree Python (Verdi)
>>0.1.0 Bredls Python (Smurfette)
>>0.2.0 Feline (Pippen and Pandora)
>>0.0.1 Desert Tortoise (Pope John Paul aka JP )
>>2.2.1 Fish (1,2,3,4)
>>0.0.0 frogs rescued from pool skimmer
>>0.0.1 Lizards of unknown origin
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Jeremy Conrad
bpConnection
_____________

...Can't...stop...must...get...more...balls...

See the link below.

In snakes the females are WZ and the males are ZZ. So the father always gives Z and daughters are caused when the mother gives W and sons when she gives Z. So the mother determines the gender on what should in theory be the long term observed 50/50 split.

However, the 16 females in a row works out to 1 in 65,536. The example of 45 females in a row 1 in 35 trillion. So, something is up here that looks to be a considerable deviation from the expected.

Where there many eggs that failed to hatch in either case? Maybe these males are homozygous for a "son killer" version of the Z chromosome (opposite of the article). Of course that bags the question of how are the fathers alive. Maybe it's only fatal when paired with a normal Z. But where the first homozygous "son killer" Z male came from would be a good question. Maybe there is some regional variation of the Z of these males that just isn’t compatible with the more common Z seen in the mothers.
ZW Species

The male has defective Z or no Z chromosomes or is simply not able to produce gametes with correct Z chromosomes (genetic problem with meiosis). Thus, the offspring only have one sex chromosome either a W or a Z (from the mother), which in either case could appear female (assuming male phenotype is a result of gene dosage from two Z chromosomes) or perhaps having one Z and no W is fatal...

>>
>>In snakes the females are WZ and the males are ZZ. So the father always gives Z and daughters are caused when the mother gives W and sons when she gives Z. So the mother determines the gender on what should in theory be the long term observed 50/50 split.
>>
>>However, the 16 females in a row works out to 1 in 65,536. The example of 45 females in a row 1 in 35 trillion. So, something is up here that looks to be a considerable deviation from the expected.
>>
>>Where there many eggs that failed to hatch in either case? Maybe these males are homozygous for a "son killer" version of the Z chromosome (opposite of the article). Of course that bags the question of how are the fathers alive. Maybe it's only fatal when paired with a normal Z. But where the first homozygous "son killer" Z male came from would be a good question. Maybe there is some regional variation of the Z of these males that just isn’t compatible with the more common Z seen in the mothers.
>>ZW Species
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when life hands you lemons, make super lemons, bumblebees, etc...

Hopefully they can keep track of some of the female offspring and see how they breed. Maybe bred to dad they could produce the expected 50% males but all would be like dad and only produce females with other lines (going on the theory that he is homozygous for a version of Z that isn't compatible with other versions). If that where the case even when the females are bred to "normal" males they would only produce females, it just would take longer to get the kind of statistical evidence that it wasn't just a fluke compared to breeding a male to several females in one year and producing only females.

0.0015%

The odds that any 16 eggs turn out to be all one sex.

That is ASSUMING that the odds of getting one sex or the other is 50/50........and that is a BIG assumption indeed.

I have a male pastel that has to date produced 45 offspring - all of them female. I have shared this information with a few other breeders and met with a bit of scepticism. I have heard that some men can only have daughters (only produce sperm with X chromosomes), so maybe it happens in snakes also. Anyway enjoy it. It's certainly a good way to increase the number of females in your collection.

Best of luck,
Dan

Normally, if you post something on KS, you will find someone has had that same "luck", with a few exceptions. Dont get me wrong, I doubted my own ability first. Then when I exhausted all the options, they are in fact females. Now....how lucky can I get, maybe they are all hets too!!! Yeah right....

What were your temps like during incubation, low temps? Fluctuations? I always seem to get more females, at lower temps but never a whole clutch.
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Jesse Jeffcoat
Gopher Hill Herps

I used a 27cubic ft fridge, heat cable and a helix DBS 1000 set at 88. I monitored the inside of the egg boxes during incubation and the temps always stayed between 88 and 89. Two clutches hatched at day 55 and the other at day 57.

I also had a Het Pied male x Normal female clutch of 5 eggs in the same incubator. It too hatched out at day 55 with 4.1. We never had a power loss and whenever I checked the inside temps they were always right there.