Windows to Eyes: A Left Brain Perspective

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I have always been obsessed with the subject of the eye as the window to one’s soul. In art, I am inspired by surrealists such as Kahlo, Dali, Man Ray, and The Man Magritte. As a scientist and educator, I translate this interest in the fields of genetics and technology.

The eye is a fascinating organ. The iris  is used as a biometrics tool, and iris scanning is used by many airports (though more frequently in Europe than here in the United States, presumably due to cost-effectiveness). The iris is less likely to change, even after surgery.

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Is it possible for Josh to be blue-eyed if both his parents are brown-eyed? This initial question is my ultimate anticipatory set tool for lesson planning. It engages students both at the secondary and higher education levels, and an inquiry that starts with eye color inevitably transitions into a panoply of genetics-related concepts.

In genetics, color-blindness and hemophilia are the classic examples of  sex chromosome-related and inherited genetic disorders. Prior to this is a discussion of the photoreceptors in the eye that allow distinction among colors. Animals see differently than humans. The mantis shrimp is not only a beautiful crustacean but an organism that has twelve different photoreceptors  .

peacock mantis shrimpMantis_shrimp

On land, human eyesight (left) may be compared and contrasted with that of dogs (middle) and birds (right).

Untitled   dog vision  bird vision

Cataracts, the clouding of the lens of the eye, is a degenerative disorder that is age-related. An article cites that birds that are characterized by brightly-colored feathers have a higher incidence of cataracts. In comparing the different species, it was found that these birds were linked by a common pigment called Pheomelanin, which is responsible for bright coloration in birds and, interestingly, red hair and freckles in humans.

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This finding is currently tied to current studies in human cataracts. The article led me to an ophthalmology research publication that discusses how cataracts affect vision, and the discussion focuses on Monet’s art before and after his cataracts became severe.

Left to right: Giverny  bridge photograph; Monet’s painting prior to the manifestation of cataracts

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Left to right: the bridge as may be seen by moderately severe cataracts; the bridge, as may be seen by disabling cataracts.

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Windows to Eyes

 References:

Ask a Biologist (2014). How do you know if an animal can see color? ASU School of Life   Sciences.   Retrieved from https://askabiologist.asu.edu/colors-they-see

Images from the following sites: http://www.moma.org/collection/object.php?object_id=7893

http://www.arthistoryarchive.com/arthistory/surrealism/Frida-Kahlo.html

http://bit.ly/1Ayxx8g

http://bit.ly/1za7W1g

http://bit.ly/1F4TrxV

www.starizona.com

http://www.pbs.org/weta/fridakahlo/resources/locations.html

http://www.nga.gov/content/ngaweb/Collection/highlights/highlight74796.html

Marmour, M. (2006). Ophthalmology and art: Simulation of Monet’s cataracts and Degas” retinal diseases. Journal of the   American Medical Association Ophthalmology, Arch Ophthalmol. 2006;124(12):1764-1769. doi:10.1001/  archopht.124.12.1764

National Eye Institute (2014). Cataracts. Retrieved from https://www.nei.nih.gov/eyedata/cataract

Nature News (2014). Animal colour through animal eyes. British Broadcasting Company. Retrieved from http://  http://www.bbc.co.uk/nature/18580667

Nature News (2014). Red-feathered birds suffer from eye damage. British Broadcasting Company.

http://http://www.bbc.co.uk/nature/17769407

Stanford at the Tech Museum (2014). What color will your children have? The Tech Museum of Education. Retrieved from

http://genetics.thetech.org/online-exhibits/what-color-eyes-will-your-childrenhave

Statistic Brain (January, 2014). Eye color distribution percentages. American Academy of Ophthalmology. Retrieved from   http://www.statisticbrain.com/eye-color-distribution-percentages

Is our DNA our destiny? Epigenetics

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I introduce genetics by engaging students in a discussion of eye color. Mendelian genetics and the basic laws of dominant and recessive traits transition to the inheritance of traits and disorders. There is always the inevitable question: If I inherit the gene that is related to alcoholism, is that my destiny? Why do some identical twins, naturally occurring clones of each other, differ in their health as they get older?

Epigenetics is the study of chemical reactions that occur during the development of an organism and activate or deactivate certain parts of the genome. Think of genetic switches that can be turned on or off during various stages of our lives. This relatively new focus hints at environmental influences on gene expression.

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In this audio slide show, two genetically identical twin mice are compared. The left one is obese and prone to diabetes, whereas its twin on the right is lean and less likely to express diabetes. The cause is attributed to epigenome, which is being compared to a second genome within an organism.

The study of epigenetics is truly a breakthrough in the study of gene expression and the influence of environmental factors.

STEM CELLS AND YOUR GENES

Stem cell research is always controversial until it hits home. What if Mom starts becoming symptomatic with Huntington’s Chorea and is positively diagnosed? Children have a 50% chance of inheriting this dominant autosomal genetic disorder. If our child is diagnosed with a disorder such as Tay Sachs or Cystic fibrosis, would we then consider any and all possible options? Research has opened new doors to management and treatment of genetic disorders.

The harvesting of stem cells from embryos has given way to the study of stem cells through other methods, such as adult stem cells. A Japanese scientist, Shinya Yamanaka, discovered how to turn back time on adult rat cells and convert them into the equivalent of embryonic stem cells. Stem cells are pluripotent, that is, they can be induced to become any cell in the human body. A series of TED talks on the future of stem cells is worth exploring.

     GENETICS OF HUNTINGTON’S CHOREA: Chromosome 4

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GENETICS OF TAY SACHS AND CYSTIC FIBROSIS: Both parents must have the gene for the trait  (Tay Sachs, Chromosome 15; Cystic fibrosis, Chromosome 7)

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Dissecting Chromosomes with Bioinformatics

Bioinformatics is an integration of computer technology into the study of biological data, specifically with regards to genetics and genome. What traits and disorders are associated with each of our chromosomes? A great and authoritative source for bioinformatics is ncbi. The site is formidable at first glance, and I am grateful for the opportunity to attend a week-long workshop at UC Davis a few years ago. I  had a whole suite of dorm rooms to myself for the duration of the conference. And yes, the epitome of nerd-dom is enjoying five days of 8-5:00 PM computer time on a genetics database.

At the secondary level, high-school biology students can be cognizant of the new fields for undergraduate focus, such as bioinformatics and biotechnology. Additionally, genetics is a great “hook” to engage students in the application of science concepts to their real-life experiences.

The Pub-Med resource of this site is understandable to non-techies.

UC Davis Institute of Bioinformatics

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Downtown Davis

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And….a little side excursion at  a local winery…

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Bioinformatics genetics epigenetics