11/21/2023 0 Comments Genetic mutation purple eyesPhysicist Isaac Newton even added two colours to the rainbow-orange and indigo-bringing the total to seven (red, orange, yellow, green, blue, indigo, violet) so that the colours would be divided after the manner of a musical chord. Berlin and Kay identified 11 possible basic colour categories, starting with white/black, red, green/yellow, blue, brown, purple/pink/orange/grey. Researchers of language show that many words for colour have developed differently, the obvious explanation being the environment that people were living in and the objects that they needed to describe. Whilst the Young–Helmholz trichomatic theory of colour vision (now explained by the presence of three different colour opsin genes) suggests we can define all our perceived colours as mixtures of red, blue and green (or with our colour printers using complementary colours: cyan, magenta or yellow), there is no agreed ‘definition of eye colour’ and there are challenges in consistency of describing colours across different languages and cultures. And in that darkness, eyes staring back at me. Viewers tried to predict events based on eye colour, “I see a darkness in you. Capturing the attention of the public with eye colour and genealogies was done marvellously by the TV series (and books) of Game of Thrones. Individuals of Asian or African ancestry, most of whom have brown eyes, can still look at other families. Many people can look at the eye colours in their own families and draw their own pedigrees to see how the Mendelian model applies. This Mendelian-Complex genetic explanation for eye colour also crosses over into the genetics of many other eye diseases such as age-related macular degeneration and glaucoma. This may have inspired his own interest in genetics, as he and his identical twin brother had brown eyes and their parents had blue! We now know that eye colour is actually a complex genetic trait, involving interaction of some major genes and many minor genes. Geneticist Victor McKusick stated, “The early view that blue is a simple recessive has been repeatedly shown to be wrong by observation of brown-eyed offspring of two blue-eyed parents”. There are intermediate variations of green and hazel, as well as albino eyes, which lack pigment entirely-all examples for which the simple Mendelian model does not apply. In the near future, patients will attend eye clinics with genetic results showing they are at high risk of certain eye diseases and ophthalmologists will need to know how to screen, follow and treat these patients.īlue or brown describes only a portion of eye colour. We need to ask every patient about their family history. Genetics should be part of the armamentarium of every practicing ophthalmologist. Genetics is relevant, not just for Inherited Retinal Diseases and congenital abnormalities but also for the leading causes of blindness: age-related macular degeneration, glaucoma, myopia, diabetic retinopathy and cataract. As the explosion of data from genomics, big data and artificial intelligence transforms medicine, ophthalmologists need to be genetically literate. These themes in popular culture can be leveraged as tools to teach and engage everyone in genetics, which is now a key component in all eye diseases. Television shows such as Game of Thrones focused attention on the eye colour of characters, as well as their Dire-wolves and Dragons. Beyond genetics, colour perception touches on concepts involving optics, physics, physiology and psychology and can capture the imagination of the population, as we saw with social media trend of “#the dress”. Eye colour and colour perception are excellent examples to use when teaching genetics as they encompass not simply the basic Mendelian genetics of dominant, recessive and X-linked disorders, but also many of the new concepts such as non-allelic diseases, polygenic disease, phenocopies, genome-wide association study (GWAS), founder effects, gene-environment interaction, evolutionary drivers for variations, copy number variation, insertions deletions, methylation and gene inactivation.
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