photo courtesy of The Urban Reptile

According to biology-online.org a polygenic trait is described as:

Polygenic traits are controlled by two or more than two genes (usually by many different genes) at different loci on different chromosomes. These genes are described as polygenes. Examples of human polygenic inheritance are height, skin colour and weight. Polygenes allow a wide range of physical traits. For instance, height is regulated by several genes so that there will be a wide range of heights in a population.

In Leopard Geckos polygenic traits are also called line bred traits. All the lines of Tangerine, Carrot Tail and non genetic snows are all polygenic. One of the reasons why the animals that best represent any of the line bred morphs hold their high value is because unlike simple recessive, dominant or co-dominant genes there is no guarantee that a certain amount of the offspring will be as perfect let alone even show the trait. In addition it can take many years to perfect them.

Lets take Carrot Tail as an example. If we breed two geckos with 75% carrot tails together the resulting hatchlings have a high probability of having carrot tails but the level of carrot tailing is not certain at all. To put it in genetic terms, the phenotype (visual representation) that results from that pairing is a combinations of many genetic factors. Of course breeding animals that show the trait skew the odds in our favor.

Another example of this is when we breed two geckos together and the resulting hatchlings show a high level of carrot tailing even when the parents don't. This is most likely because among the many genes that need to be turned on to the carrot tailing the parents alone didn't have enough of those genes switched on to show the phenotype but were able to pass on the needed genetics to their progeny.

This brings me to the Reptile Calculator. We have had a few comments asking why we are missing morphs such as Sunglow, Tangerine, Carrot Tail and other line bred traits. This is by design. Since we cannot tell you with any accuracy at all the percentage of offspring that will show any of those traits or how well that trait will be represented. Because we can't calculate these things we have chosen to leave them off our list. If we were to include the Sunglow, from a genetic standpoint, it would simply be a Hypo Tremper Albino in the results.

While we have used Leopard Geckos here the same would apply to a line bred morph for any animal.

We have given thought to adding these traits to the Reptile Calculator and then displaying a line at the bottom of the results saying that you may see the trait. From our perspective that isn't really a calculation. However, if you feel this is important and would help you please comment below or send us a message on Facebook and we can add this in one of our upcoming updates. Also, don't hesitate to contact us with any questions or comments. The feedback is very helpful and we want to make sure that you are getting the most out of the Reptile Calculator.