Banana ball python genetics turn the greener sections of a wild type ball python into bright yellow, and the black sections into a soft gray. This striking morph only became well publicized in the early 2000’s, but as a co-dominant trait it’s been a good one for breeders around the world to work with.
Banana vs Super Banana
Banana is a dominant trait because a ball python that carries a single gene for this phenotype will have an outward expression of the colors their DNA is now coding for.
But it can also be described as co-dominant. This is because if you have a pair of these genes, one from each parent, then something even more fantastic happens to their shading. A super banana is one that carries two of these dominant genes.
Super bananas have even brighter yellow markings, and even more pale grey to creamish areas where the black would have been present.
You don’t come across them too often, but they look even more gorgeous in real life than in the images you’ll find online. And they are awesome for breeders who want to work with the banana gene, because every single baby produced will carry this expressive trait.
Banana is a Sex Linked Gene
The gene that causes the banana morph is an unusual one because it sits on an allele of the chromosome that determines sex. So on a male snake it could either sit on the X or Y. A female snake will have it on one of their pair of X chromosomes.
Female vs Male Makers
An adult male snake has the potential to be a male maker or female maker. This means that a particular male snake will only ever throw male or female banana babies.
Mothers will make half or each, because they only have X chromosomes to pass along.
Let’s break that down.
Just like humans, female pythons have XX chromosomes, and males have XY.
The mother can only pass along an X from that pair, but the father has even odds of passing along an X or a Y to the baby.
Simple Banana Ball Python Genetics
If the banana gene sits on the father’s Y chromosome it will only pass to male offspring. His daughters can’t ever be banana, unless the mother also carries it.
If banana resides on the male’s X chromosome, all the female babies will have that banana gene instead. But it can’t be passed along to the males, because there is no banana on the Y.
When Both Parents Carry One Banana Gene
When the dad has the banana gene on his Y gene, all male babies will be bananas and half female babies will be too.
But if his gene is on the X, all the female babies will be bananana and half the male babies will be banana.
But there is another possible outcome, and that’s the super form of banana, where there are two banana genes. A super banana will have all banana baies, regardless of the genes carried by the other partner.
Random Chance in Banana Ball Python Genetics
Occasionally a male or female maker will throw a banana of the opposite sex to confuse matters. This happens very rarely when as a fertilised egg splits the chromosomes cross from one side of the division to the other.
There are some enthusiastic arguments online about the likelihood of this happening, but reasonable odds seem to be around five percent.
Are Banana Ball Pythons Healthy?
The odds of your banana being unhealthy are nice and low, anecdotally similar to a wild type. This is because this gene is so easy to duplicate, so there hasn’t been a reason for breeders to line breed the trait. Which is a tactic that accidentally also increases the chances of your snake inheriting a nasty genetic disease as well as a cool genetic color.
They haven’t been associated with neurological issues or structural defects that can go along with some popular morphs.
Color vs Temperament
Snakes aren’t domesticated in the way that our mammalian pets are. They basically display the same behaviors that they would have in the wild, but with some variances to account for their socialization and treatment growing up.
Your banana ball python will have a good chance of being just as chill, shy and sedentary as the average wild type.