# Ball Pythons > BP Morphs & Genetics >  How can a male snake be a "female maker" or "male maker"?

## kaitala

I've seen ads for male snakes as "female maker" or "male maker".  

If the females are the heterogametic (zw) gender, how does the zz of the male determine sex?

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## ajmreptiles

Its a genetic anomaly with the Banana/coral glow gene. visual males produced from banana/coral glow females will produce around 95% female visual offspring and are called female maker males. Every so often it will produce a visual male and will have the same statistics in its offspring but will be predominately males and is called a male maker. Its weird and confusing

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PeterPieBaldPython (08-06-2015)

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## kaitala

Thank you for that, but I'm still rather confused.

The female determines the sex, as she is the one that would throw the z or the w.  The male has no choice but to throw Z's.

Wouldn't the female be the "female maker" or the "male maker"?

How is this proven?  

If Banana is co-dom, aren't all bananas visual?

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## paulh

Right. The female determines the sex, as she is the one that would throw the Z or the W. The male has no choice but to throw Z's.

As far as I know, all bananas are visual. "Male makers" and "female makers" are in banana male x normal female matings. Both male and female babies occur. But with male-maker males, there are both normal and banana male babies while almost all the females are normal instead of banana. Female-maker banana males produce the reverse. Someone correct me if I am wrong here.

All this confuses everybody. My own guess (and it's only a guess) is that the banana mutant gene somehow affects the sex hormone levels as well as color.

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## OhhWatALoser

It really isn't that confusing.  If the male banana came from a male banana,  it will make mostly male bananas.  If the male banana came from a female banana,  it will make mostly female bananas. Sex ratios don't change.  Female bananas produce as expected. At least that is the conclusion we can come to with the current info. 

Mechanics behind it are unknown,  it is an anomaly never seen before. Z's and W's might play some sort of factor,  but the gene is not sex linked. Otherwise we could say it is linked to Z or W.

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_Dave Green_ (12-09-2014),kaitala (12-09-2014)

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## kaitala

Okay, so let me see if I got this:

 when the male carries the one codom gene for banana on his W, he'll be a "banana male maker" and when bred to a normal, she'll throw normal females (from his normal Z gene) and banana males from his W gene which carries the banana...  reverse for females...  The few exceptions of visuals have to be created during gene transfer in meiosis, and are necessary for the super forms....

Are there differences in appearance between the two?  

Wouldn't this be true of all co-doms?

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## TessadasExotics

> It really isn't that confusing.  If the male banana came from a male banana,  it will make mostly male bananas.  If the male banana came from a female banana,  it will make mostly female bananas. Sex ratios don't change.  Female bananas produce as expected. At least that is the conclusion we can come to with the current info. 
> 
> *Mechanics behind it are unknown,  it is an anomaly never seen before*. Z's and W's might play some sort of factor,  but the gene is not sex linked. Otherwise we could say it is linked to Z or W.


Actually it is not something never seen before and the mechanics behind it are quite obvious. This is the first in ball python genetics that we have seen, but definitely not the first sex linked gene in the animal kingdom.

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luizillo (09-04-2019)

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## OhhWatALoser

> Okay, so let me see if I got this:
> 
>  when the male carries the one codom gene for banana on his W, he'll be a "banana male maker" and when bred to a normal, she'll throw normal females (from his normal Z gene) and banana males from his W gene which carries the banana...  reverse for females...  The few exceptions of visuals have to be created during gene transfer in meiosis, and are necessary for the super forms....


Males have homozygous sex chromosomes, usually represented as ZZ. Again it is not sex linked. It is a never before seen anomaly.




> Are there differences in appearance between the two?


no




> Wouldn't this be true of all co-doms?


They sit on one of the other chromosomes that are not described as sex chromosomes.

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## OhhWatALoser

> Actually it is not something never seen before and the mechanics behind it are quite obvious. This is the first in ball python genetics that we have seen, but definitely not the first sex linked gene in the animal kingdom.


How many years are you going to be saying it despite glaring evidence of it not falling under the definition of sex linked?

Even though we have done this before in other places, why not on bp.net.... please enlighten us Tess, tell us how it works.

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## TessadasExotics

Little run down of sex linked traits/bio_4.htm

another cool link on the subject


More sex linked and linked genetics

all really good reading.

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## OhhWatALoser

I am very aware of how sex linked genes work, banana/cg does not follow that model.

If the gene is Z linked, we would see normal ratios with males, and female bananas would throw all male bananas and all female non-bananas.

If the gene is W linked we would only see female bananas.

So again please enlighten us.

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## TessadasExotics

Glaring evidence of what? It's just some whacked out phenomena that no one can figure out? Guess what, it has been figured out and it works the same every time for the Banana/CG. Only a few who try to refute the overwhelming evidence because they think they are special.

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## TessadasExotics

OK let me make it SIMPLER for you.


Haldane's Rule

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## OhhWatALoser

> Glaring evidence of what? It's just some whacked out phenomena that no one can figure out? Guess what, it has been figured out and it works the same every time for the Banana/CG. Only a few who try to refute the overwhelming evidence because they think they are special.


My reasons are already stated above why it does not fall under the definition of sex linked.




> OK let me make it SIMPLER for you.
> 
> 
> Haldane's Rule


lol? I guess I'm too dumb to understand how this has to do with a rule that appears to focus on null chromosomes. Please spell it out for the world because up until this point no one else has. You could make ball python history. Or you can keep posting links and making claims with no evidence.

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## TessadasExotics

Ok.
_Assume first female is an f1_ 
Female Bananas produce male and female offspring in apparently normal ratios.
Male (f1) bananas produced from female(f1) bananas will produce mostly male Bananas. We can assume it to be 99% of the time. All normal or non Banana offspring are regular male/female ratios.
If a female (f2) is produced from a "male maker" (f1) Banana, She will produce males and females at normal ratios, but any male (f2) Banana will now make females and males at in normal ratios.

So it is a sex linked recessive gene which does happen and is illustrated and explained in the previous links I posted for you.

Why is this so hard for you to understand?

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## OhhWatALoser

> Ok.
> _Assume first female is an f1_ 
> Female Bananas produce male and female offspring in apparently normal ratios.
> Male (f1) bananas produced from female(f1) bananas will produce mostly male Bananas.


Breeding record show that they will produce mostly female bananas..... hence why it took so long for the project to pick up steam, male makers didn't exist for a long time.




> We can assume it to be 99% of the time. All normal or non Banana offspring are regular male/female ratios.


We have only observed this with offspring from female bananas. Males throw skewed ratios.




> If a female (f2) is produced from a "male maker" (f1) Banana, She will produce males and females at normal ratios, but any male (f2) Banana will now make females and males at in normal ratios.


I have not heard of a case of any male banana throwing normal ratios.




> So it is a sex linked recessive gene which does happen and is illustrated and explained in the previous links I posted for you.
> 
> Why is this so hard for you to understand?


I guess it hard for me to understand because you are reporting something that is nearly 100% different from everyone else.

Also the flaw in it being sex linked already lies within how the female production behaves, which is about the only part I can agree with you on. Which is normal bananas throw normal ratios like any other gene correct? How do you get normal sex ratios from a normal male (ZZ) x female banana (ZW) if the gene is sex linked?

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_Dave Green_ (12-09-2014)

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## TessadasExotics

Here is a nice write up from Mr. Lawson.
Guide-on-Sex-Linked-Mutations

Maybe you will accept this fact from him?

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## OhhWatALoser

> Here is a nice write up from Mr. Lawson.
> Guide-on-Sex-Linked-Mutations
> 
> Maybe you will accept this fact from him?


Do you even read the links you post? Look in the posts and even back then they bring up examples to prove him wrong.  Even his OP flawed.   3 years ago there was a lot of confusion with the gene.  I don't blame him at all,  I respect the hell out of him actually,  but 3 years ago he was wrong,  given we have 100x the public breeding records now.

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## TessadasExotics

Sure do. My point is is that he has a much better grasp on it than you do. Most people I talk to understand how it works... Not sure why its so hard for you to?

Anyways I'm done beating a dead horse. I explained how it works and how it is sex linked. It's not some unexplainable anomaly and does happen in other animals as well as people.

Keep on keeping on  :Good Job:

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## OhhWatALoser

> Sure do. My point is is that he has a much better grasp on it than you do. Most people I talk to understand how it works... Not sure why its so hard for you to?


lol you read it really?




> From this breeding, we get a 1:1 ratio of animals with a ZcZ+ genotype to animals with a Z+W genotype. All of these animals express the wild-type phenotype. Because all of the females get their W-chromosome from the mother and their Z-chromosome from the father, none of them carry the coral glow mutation. However, any males in the clutch will be heterozygous for coral glow because all of them will get one Z-chromosome containing the mutation for coral glow from the mother. Note that it is IMPOSSIBLE to obtain a female expressing the wild-type phenotype to carry a mutant Z-linked allele - therefore, there is no such thing as a female het coral glow.


Read past the OP




> Randy, I think I might have found the thread you were talking about. A male banana to female pinstripe produced a male banana...
> 
> http://ball-pythons.net/forums/showt...80#post1390980
> 
> So this is at least one instance where the offspring do not follow the expectations for a Z-linked mutation. I'd really like to see information on the parents of the rest of the male bananas and coral glows out there. I know there aren't too many.


Now we have hundreds of instances. 




> Anyways I'm done beating a dead horse. I explained how it works and how it is sex linked. It's not some unexplainable anomaly and does happen in other animals as well as people.
> 
> Keep on keeping on


You posted a few links that do not explain the anomaly we are seeing and an explanation that goes against all available information.  :Good Job:

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## Eric Alan

I'm just putting this out there for my own clarification - feel free to correct me if I'm mistaken:

From my understanding, whichever parent is the Banana trait carrier will determine what sex Bananas the male Banana offspring will predominantly produce.
If a male Banana is produced from a female Banana, this male Banana will produce predominantly female Bananas (a "Female Maker").If a male Banana is produced from a male Banana, this male Banana will produce predominantly male Bananas (a "Male Maker").
Thanks for your insight in advance!

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## Dave Green

> I'm just putting this out there for my own clarification - feel free to correct me if I'm mistaken:
> 
> From my understanding, whichever parent is the Banana trait carrier will determine what sex Bananas the male Banana offspring will predominantly produce.
> If a male Banana is produced from a female Banana, this male Banana will produce predominantly female Bananas (a "Female Maker").If a male Banana is produced from a male Banana, this male Banana will produce predominantly male Bananas (a "Male Maker").
> Thanks for your insight in advance!


Correct, and female bananas produce typical sex ratios.

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_Eric Alan_ (12-09-2014)

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## Eric Alan

> Correct, and female bananas produce typical sex ratios.


Of which I know you're selling a few.  :Wink:

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## Spiritserpents

If the *female* determines the gender, the only way I can see a *male* snake throwing *male* babies is if male bananas are actually actually ZZW, rather like how male calico cats are XXY.  But, then, the male bananas should be mostly sterile, so that doesn't work either.

Other option, the female chromosome is often incompatible with the banana-carrying genome, causing failure to develop, along the lines of the fabled 'super spider'?

*flails* this is really strange and really doesn't make sense.

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## Eric Alan

> *flails* this is really strange and really doesn't make sense.


Says the entire BP community...

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PeterPieBaldPython (08-06-2015),_se7en_ (08-29-2015)

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## TessadasExotics

> If the *female* determines the gender, the only way I can see a *male* snake throwing *male* babies is if male bananas are actually actually ZZW, rather like how male calico cats are XXY.  But, then, the male bananas should be mostly sterile, so that doesn't work either.
> 
> Other option, the female chromosome is often incompatible with the banana-carrying genome, causing failure to develop, along the lines of the fabled 'super spider'?
> 
> *flails* this is really strange and really doesn't make sense.


Actually it is the male that determines the sex. Also just because male Calico cats are mostly sterile does not mean that this would apply in ball pythons as they are not calico house cats.

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## Spiritserpents

Uhmmm... no... in snakes, and birds, the female is the heterozygote and the male is the homozygote, opposite of mammals.

So in snakes, the *female* determines the gender of the offspring.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3754893/




> *In snakes, females are the heterogametic sex, in that they have two  different sex chromosomes, Z and W, while males have two Z chromosomes.*

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kaitala (12-13-2014),_TessadasExotics_ (12-12-2014)

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## TessadasExotics

lol I forgot that reptiles and birds were backwards. 

That is a great article and interesting to see that morphology (and faster evolution/genetic drift) is caused by the males.

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## Lady mkrj58

Great thread :Smile:

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## paulh

> ....
> 
> Other option, the female chromosome is often incompatible with the banana-carrying genome, causing failure to develop, along the lines of the fabled 'super spider'?
> 
> *flails* this is really strange and really doesn't make sense.


My understanding is that a banana female mated to a normal male produces equal numbers of male normals, female normals, male bananas, and female bananas. If that is correct, then the W chromosome is compatible with the banana-carrying genome.

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## kaitala

I have been thinking about this and there is just no good explanation for the male being either a "male maker" or a "female maker" without the allele for B/CG causing failure in the W or Z respectively.  

I went on iHerp, the only tracking site I know of, and found two coral glow outcross (meaning not breeding for a super coral glow), but the outcome of the clutch was not available.

When a "male maker" or "female maker" is bred to a normal, what is the sex ratio of ALL of the litter?  Is it near 50/50 or is it gender heavy in favor of the sex of the b/cgs?

Have the normal females been bred to other snakes?  Are the ratios similar?  Has the male been bred to other normal females with similar ratios?

Where are we actually getting the data for this "male/female maker"?  How many breedings are required before one can say it's a gender maker, not just luck of the draw on one clutch?


Makes me want to go back to school so I can do a Masters Thesis on this.....

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## Dave Green

I've produced clutches from banana females, a male maker banana and a female maker banana (that I produced myself from one of my banana females).  I haven't produced a lot of clutches but probably 15 clutches or so overall.  Without checking my records I've produced 4 clutches from my two females and the sex ratios have been normal and about half were bananas.  Out of an estimated 10 clutches from my male maker and female maker only 3 babies have broken the male maker/female maker rules.  If you breed a male maker banana male to any female the overall sex ratio is normal but all the males are bananas and all the females are non-bananas.  The opposite is true from a female maker. I've talked with other breeders and they all seem to report the same thing.

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kaitala (12-13-2014),_paulh_ (12-13-2014),PeterPieBaldPython (08-06-2015)

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## TessadasExotics

The information is out there. The Banana/Coral Glow has been around for over 10 years. I know Kevin had em at least as early as 2002. Sad to think that the information was just recently released about the sex-link issue. But I guess it's not surprising knowing how long the spider issue took to come to light.

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## OhhWatALoser

I have no personal experience, but I have friends who have bred them and talked to many breeders who have. Also many reports are scattered across the internet. So with the information available....




> When a "male maker" or "female maker" is bred to a normal, what is the sex ratio of ALL of the litter?  Is it near 50/50 or is it gender heavy in favor of the sex of the b/cgs?


sex ratio is normal, just with say a male maker, the males will be bananas most of the time thus the non-bananas will mostly be female.




> Where are we actually getting the data for this "male/female maker"?  How many breedings are required before one can say it's a gender maker, not just luck of the draw on one clutch?


If the male banana came from a male banana, it is a male maker
If the male banana came from a female banana, it is a female maker
If you produce a female banana from a female banana, male maker, or female maker, it will produce as expected like any other gene.

That has been proven over and over through many breedings. No proving out needed, just need to know what parent the gene came from. Someone who verbally shared some numbers with me in the past was brock wagner, but every banana breeding has confirmed the above statement that I have seen.

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## kaitala

> I've produced clutches from _banana females, a male maker banana and a female maker banana (that I produced myself from one of my banana females)_.  I haven't produced a lot of clutches but probably 15 clutches or so overall.  Without checking my records I've produced 4 clutches from my two females and the sex ratios have been normal and about half were bananas.  Out of an estimated 10 clutches from my male maker and female maker only 3 babies have broken the male maker/female maker rules.  If you breed a male maker banana male to any female the overall sex ratio is normal but all the males are bananas and all the females are non-bananas.  The opposite is true from a female maker. I've talked with other breeders and they all seem to report the same thing.





> If the male banana came from a male banana, it is a male maker
> If the male banana came from a female banana, it is a female maker
> If you produce a female banana from a female banana, male maker, or female maker, it will produce as expected like any other gene.
> 
> That has been proven over and over through many breedings. No proving out needed, just need to know what parent the gene came from. Someone who verbally shared some numbers with me in the past was brock wagner, but every banana breeding has confirmed the above statement that I have seen.



Now the confusion grows, just when I thought I was starting to get it!

Dave said he produced his male-makers and female-makers *from his banana females*.  So that shoots down the theory that "if a male banana came from a female banana, it is a female maker".

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## Eric Alan

> Now the confusion grows, just when I thought I was starting to get it!
> 
> Dave said he produced his male-makers and female-makers *from his banana females*.  So that shoots down the theory that "if a male banana came from a female banana, it is a female maker".


You're misintrepting what Dave said. He said that he has produced clutches from all three kinds of bananas - female bananas, male-maker male bananas, and female-maker male bananas. He then added that the female-maker male banana is one he produced himself from his own female banana.

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_Dave Green_ (12-14-2014)

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## asasix

What about the super banana... does it show weird sex ratios as well?

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## OhhWatALoser

> What about the super banana... does it show weird sex ratios as well?


Being produced last year, I haven't seen any clutch data from a super yet, but I am very interested in what they will produce.

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kaitala (12-23-2014)

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## OhhWatALoser

> Dave said he produced his male-makers and female-makers *from his banana females*.  So that shoots down the theory that "if a male banana came from a female banana, it is a female maker".


I wouldn't call it a theory at this point, its pretty much proven.

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## Dave Green

> You're misintrepting what Dave said. He said that he has produced clutches from all three kinds of bananas - female bananas, male-maker male bananas, and female-maker male bananas. He then added that the female-maker male banana is one he produced himself from his own female banana.


Correct, my male maker banana was produced from a male banana.  Sorry for any confusion.

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kaitala (12-15-2014)

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## ballpythonenthusiast

> lol I forgot that reptiles and birds were backwards. 
> 
> That is a great article and interesting to see that morphology (and faster evolution/genetic drift) is caused by the males.


Pretty sure this is what caused your misconception about it being sex-linked when most people think it's not. Plus, the fact that bananas are codominant pretty much renders the sex-linked theory impossible. It's still pretty perplexing why mutations in the male would cause a skewed ratio assuming that the same number of babies are produced (ie. assuming females or males don't die before they're hatched).

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## PeterPieBaldPython

Do you know who produced a 'super banana' and what gender it was? 

It's still possible that the trait is sex-linked because Z and W may be able to engage in crossing over (I can't find anything in the literature 'for' or 'against' this - anyone know of any studies? birds or reptiles. insects do crazy stuff, so not usually as applicable).
 Cross-over events are rarer as two genes get closer together, so a 'banana male maker' producing 95% male/banana & 5% female/banana ratio would be really neatly explained by two neighboring genes crossing over. statistically beautiful, really.

Science studies mammals more often, but X and Y don't really crossover (the size difference keeps them from hooking up properly), so 'what's there is there'. e.g. you can't get calico cat coat color genes "orange" and "black" off of the X and on to the Y (Y doesn't have a color locus at all, so there's nothing for X to trade with = no crossing over); you have to have non-disjunction events (resulting in XXY) to get a 'male calico' but the calico male is sterile (because making gametes with 3 copies of a chromosome is *not* pretty and hormone dosage in mammals is tricky and must be perfect in order to get proper adult genitalia - you're sterile without fully functional testes).

There is no 'model reptile' (there is a 'model' plant, bacterium, fungus, and mammal - where basic questions like this are first answered). Back in 2007, a research group found that temperature could influence sex ratio EVEN IN genotypic (ZZ male / ZW female) species (http://www.sciencemag.org/content/316/5823/411.short). 
If "W" isn't 100% necessary for functional females, then banana may well be 'sex-linked'. It's also possible ZZW females aren't sterile (and Z_ males for that matter) - lots of organisms tolerate genetic mishaps far better than mammals.

Since so little is known about sex determination in the snake clade, it's also possible there are other factors involved we haven't even fathomed. 

The ratios are super cool and the whole mystery is really intriguing.  :Very Happy: 

Right now, my money's still on crossing over between Z and W, but my heart wants it to be something TOTALLY UNKNOWN!!

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_distaff_ (08-16-2015),Tsanford (08-07-2015)

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## chosen2030

Sorry if this has already been asked, but are there other morphs that "female makers" and "male makers" occur with?

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## OhhWatALoser

> Sorry if this has already been asked, but are there other morphs that "female makers" and "male makers" occur with?


nope

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chosen2030 (08-16-2015)

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## distaff

So, one of the problems with solving this may be that we assume all fertile females are zw, and all fertile males are zz, which may not be the case?  

Is there an easy, cheap test for determining if breeding animals are, in fact, standard zw or zz?

Do these fertile anomalies produce standard zw's and zz's, in 50/50 ratio, or does the anomalous gene tend to propagate down the line?  That is, for example, are zzw females producing more zzw's?

Agree, cross-over would seem to be the simplest explanation, but I'm wondering about some odd ball possibilities as well (unintentional pun).  Unfortunately, my college biology was a LONG time ago!

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## OhhWatALoser

Last thing I read about it, which was quite a few years ago so things might of changed, but I read something about looking at the burm genome and they were just happy they figured out which was Z and which was W. they didn't see too far along in having a good base line to figure things out. Maybe things have changed though.

Problem with crossing over or not, is females produce normal ratio as far as we know, if it sits on a sex chromosome we shouldn't see that. sitting on Z of the female would lead to no female bananas and all males being bananas. Those males would be the ones producing the 50/50 split we see in females. If it sat on the W, we would only see female bananas. Now obviously cross over could come into play, but to think a crossover would happen to replicate a 50/50 split is a little far fetched. Also even with cross over the males should still be doing the 50/50 split.

Some have brought up the possibility of males being the ZW and females being the ZZ in ball pythons. But banana gene is the only evidence toward it, but we have burms that are definitely ZW female ZZ male as far as we know, which i would say is pretty close to the ball python, and a swap like that would be pretty extraordinary, not to say it is impossible tho. there just no reason to think it besides the banana gene. I don't know of any case of an XY reptiles, just ZW and temp determined ones.

The ZZW scenario might be something to think about, but I still can't seem to make it work off the top of my head, even with crossing over. Perhaps you could lay out a theory for it?

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## distaff

_"The ZZW scenario might be something to think about, but I still can't  seem to make it work off the top of my head, even with crossing over.  Perhaps you could lay out a theory for it?"                         
_
Ha!  Just shots in the dark, that's all.
My understanding of this is too vague to support anything more than the basic recessive/dominant, etc. Mendelian grids.   I'm not attached to any theories, I just find the outcomes VERY peculiar.  There has to be a reason, and the possibility of the zzw's, or even a complete flip for sex expression, etc. just looks like the most promising angle at present.

Off to do some net searches.

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## StillBP

I have been looking at the "male maker" vs "female maker" and just want to know if i got this right
If i have a female my sex ratio will be even, but all males she has will be "female makers"
if i have a "male maker" male, I will get 95% or higher males 
If i have a "female maker" male, I will get 95% or higher females 
If I do get a male form my "female maker" male, the new male will then be a "male maker" male
is that about right?

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## se7en



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_StillBP_ (08-30-2015)

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## Eric Alan

> I have been looking at the "male maker" vs "female maker" and just want to know if i got this right
> If i have a female my sex ratio will be even, but all males she has will be "female makers"
> if i have a "male maker" male, I will get 95% or higher males 
> If i have a "female maker" male, I will get 95% or higher females 
> If I do get a male form my "female maker" male, the new male will then be a "male maker" male
> is that about right?


Nope. Not "about right". Right.  :Wink:

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_StillBP_ (08-30-2015)

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## smileyguy

> Nope. Not "about right". Right.


So my question is....what is the sex ratio when you pair 2 bananas together?

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## Stewart_Reptiles

> So my question is....what is the sex ratio when you pair 2 bananas together?


*This thread is 4 years old I would encourage you to create a new one, that will get more views and more answers.

*

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dr del (09-18-2018)

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