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hen understanding snake genetics, it is important to understand the basics of homozygous, heterozygous, dominant, recessive and co-dominant genes. Every trait that is inherited by an animal is determined by a set of alleles. If one or both parts of an allele are mutated, this can cause dramatic variation within offspring. Some of these mutations are recessive, both alleles from each parent have to be mutated in the same way in order for the offspring to be different. If half of the genetic information inherited by the snake has this mutation, it is heterozygous for that particular trait. If one mutation is needed for there to be a difference, this is a dominant trait. Dominant alleles will determine the animal’s appearance regardless of whether the other allele is generic. If both alleles are the same, then this means the trait in that animal is homozygous. If the snake has one recessive and one mutated gene then it will appear to have a normal morph, and will carry the potential for this variation in colour. This means that if it reproduces with a snake homozygous for that trait then there is a 50% chance that the offspring will be homozygous for the recessive gene and display that particular morph. Co-dominant genes are a little harder to grasp. These traits are sometimes referred to within the reptile community with the word ‘super’ in front of the morph. For example, the ‘super conda’ morph, which is displayed beautifully in western hognose snakes and gives a very reduced pattern, or in other snakes such as the ‘super pastel boa constrictors’.
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