Corn snakes, why some are white

This video from the USA says about itself:

15 August 2014

The corn snake (Pantherophis gutattus gutattus) is a medium sized non-venomous colubrid that lives in the southeastern United States. Their bright colors, docile temperament, and minimum care requirements make them great for pets but it’s important to note that those you find in the wild are facing a decline in numbers and should be left alone if at all possible.

From Reptiles magazine:

Corn Snake Genome Sequenced, Albinism Mutation Detailed

November 25, 2015

By John Virata

Scientists with the University of Geneva (UNIGE), Switzerland have sequenced the corn snake Pantherophis guttatus (Elaphe guttata) genome for the first time, and discovered the mutation in the snake that causes albinism in the species, according to a paper published in Scientific Reports.

“Our aim was to produce ourselves a substantial portion of the missing data by sequencing all genes from several reptilian species. To reach this goal, we used tissues, such as the brain and the kidney, expressing the largest number of genes,” said Athanasia Tzika, researcher in the Department of Genetics and Evolution at UNIGE. “The objective was to obtain a genuine reptilian genomic model that people could rely on,” said Athanasia Tzika. “Here, we covered about 85% of the snake total genome size. There is much additional work ahead.”

The data compiled by Tzika will be freely available to researchers around the world who are working on developmental and evolutionary studies of reptiles.

UNIGE researcher Suzanne Saenko, working with Swedish scientists identified the mutation responsible for amenalism. The researchers bred a wild corn snake with a captive bred amenalistic corn snake and DNA sequenced all offspring from the cross and identified the malfunctioning gene. The gene OCA2 codes for a receptor located in the membranes of melanosomes, where melanin is found, according to the study. The receptor controls the acidity that enables the synthesis of melanin.

The researchers say that they will look into how some corn snakes are born with modified colors and patterns like longitudinal lines rather than transversal saddles that are typical of the species.