The study of genetics is fascinating, and there are some very rare and unusual genetic diseases and disorders. Mutations can also take place which can sometimes lead to some peculiar outcomes.
About 15 years ago, an octopus with only six tentacles was caught off the coast of Wales. Named Henry, his mutation was only noticed when he was taken to live in an aquarium. As octopuses are able to regrow their tentacles if they are cut off, it became apparent that he had not lost two of them. He actually did not have any space between his other tentacles for any to grow. Therefore scientists realised it was a result of his genes!
Colour mutations also take place, some being more common than others. Albinism if probably the most well known – where the pigment melanin is absent. It happens in all species, and in animals usually results in pink eyes and yellow skin. However, it should not be confused with leucism. This causes reduced pigment levels, but of all pigments, not just melanin. Animals with leucism will have normal coloured eyes – but appear to be white overall, like white tigers or lions.
Rare examples of colour mutations include the blue lobster. Shells are blue due to the over-production of certain proteins. These proteins interact with a red pigment in the crab – resulting in a blue tint.
GCSE scientists – you need to explain how diseases and blood types can be inherited. For help with this try our new guide “How to work with Genetics: Part 2”. In this guide is an explanation of how to use family pedigree diagrams as well as how diseases and blood types are inherited. There is also information on sex-linked disorders, and genetic diagrams showing how they can be inherited. It includes questions to try, and answers to check your understanding.
Click on the picture below to see the guide.
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