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When animals, including ball pythons, reproduce, they pass on their genetic information to their offspring. Each parent contributes half of the genetic information, which determines the characteristics of the offspring, such as color, pattern, and size.

Genes are the basic unit of this genetic information, and they come in different forms called alleles. Some alleles are dominant, meaning that if an individual has at least one copy of the dominant allele, it will show that trait. However, other alleles are recessive, meaning that they will only show if an individual has two copies of that recessive allele.

In ball pythons, there are many genes that determine their color and pattern. For example, the gene for pinstripe is dominant, so if a ball python has at least one copy of the pinstripe allele, it will be pinstripe. However, there are also genes for other colors and patterns that are recessive. These include genes for albino, piebald, and clown patterns, among others.


If a ball python has one copy of a recessive gene, it is called a "het" or heterozygous for that gene. It may not show the trait associated with that gene, but it can still pass it on to its offspring. If two het ball pythons mate, there is a 25% chance that an offspring will inherit two copies of the recessive allele and therefore show the associated trait. For example, if two het ball pythons for the albino gene mate, 25% on average of their offspring will be albino, even though neither parent is albino themselves.

Overall, recessive genes in ball pythons are those that only show when an individual has two copies of the recessive allele. These genes can be passed down through generations without showing in the individual animals, which can lead to surprises in the appearance of their offspring.

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