Gecko Morphs and Genetics!

This article discusses the genetics of a specific leopard gecko morph. In the pet trade, the term morph is utilized to describe different desirable color patterns, usually in which the animal is specifically bred for.

This article explored linkage and homozygosity within said morph. The allele for this more was found to be a spontaneous semidominant mutation. The researchers found that the mutation can be traced back to a locus that contains a tumor suppressor. Additionally, they studied iridophoroma in the geckos, which is the structural production of colors via crystal platelets. They discussed how research regarding specific genes in reptiles is somewhat difficult due to their somewhat long reproductive cycles and stress within laboratory breeding settings.

As someone who owns a gecko, I think that this study is very neat. I like learning about how popularity and phenotypic preference influences the pet trade and associated prices… But I do not exactly approve of breeding geckos, in a general sense. There are just so many health problems regarding breeding in captivity, and especially when it comes to traits like this article discusses. Many desired traits are often associated with chronic or lethal impacts towards the resulting individual. A good example of this is the crossing of two lily white crested geckos- it always results in death of the offspring.

Temperature Dependent Sex Determination

   What if you could hop in a sauna or chill out in an igloo to determine the gender of your child? Well, in the near future, temperature dependent sex determination will probably never happen for humans. While science may be making leaps and bounds, we mammals determine sex through genotypic sex determination (1). This means that sex is determined by genetic factors such as chromosomes and various hormones, typically predetermined at conception (2). However, during a certain period of embryonic development, the sex of most reptiles are influenced by environmental factors such as temperature and humidity. Examples of reptiles that have this mechanism, are turtles, alligators, lizards and a majority of other reptilian species, snakes being one of the few exceptions. Furthermore, in the case of turtles, "cooler nests hatch as all males, and eggs from warmer nests hatch as all females" (1).  What was most interesting to me was that there is an enzyme called aromatase that can convert sex steroids, ultimately affecting the sex of the hatchling. At low levels of aromatase, a male is produced and at high levels, a female is developed. Therefore, it would make sense then that the temperature is what is influencing the presence of this enzyme. While researchers are familiar with this concept now, a new area of focus is whether if both mechanisms for sex determination could be acting concurrently. Could there be a reptile that has sex chromosomes and could be influenced by the temperature? Researchers believe it is plausible especially after observing the Australian skink lizard. This type of species is said to have sex chromosomes, yet at low temperatures, an XX individual could appear phenotypically as a male (1).

   Although this does not have huge implications for humans, it helps us to better understand our environment. I think the next step may be piecing together how this affected evolution and even how it was selected for to begin with. The data from this type of study may not save lives but it would be fascinating to learn more about this natural occurrence.