Genetic Confusion: The Eye Color Dilemma Explained

[Docscientist]

Say a girl has brown eyes .she meets with an accident which causes her to undergo an eye transplantation.The donor has blue eyes and the girl gets them.Now does she possesses a blue or brown eye ? So she genetically has brown eyes but phenotypically has blue eyes ? Is it like that? But phenotype is controlled by genotype,isn't it ?

 

[Drakkith]

Well, the girl obviously possesses blue eyes in a physical sense. The tissue her eyes are made up of has DNA with the gene for blue eyes. The rest of her body has DNA with the gene for brown eyes.

So she genetically has brown eyes but phenotypically has blue eyes ? Is it like that? But phenotype is controlled by genotype,isn't it ?

This is not a situation where you can use phenotype and genotype since the girl's eyes are not her original eyes. Or, if you are going to use those concepts, then you have to clearly distinguish between the tissue in her eyes, which originally came from another individual, and the tissue in the rest of her body.

 

[Docscientist]

This is not a situation where you can use phenotype and genotype since the girl's eyes are not her original eyes. Or, if you are going to use those concepts, then you have to clearly distinguish between the tissue in her eyes, which originally came from another individual, and the tissue in the rest of her body.

Why can't these concepts be used? I don't understand.Do you think it is not possible to insert a blue color eye in a girl who possesses a brown eye color gene ?

 

[jim mcnamara]

I'm going to cover what I need to make sense of this question. Hmm - may regret it deeply.
A comment and then an answer:
Your questions seem to me to reveal lots of deep misunderstandings about Biology mixed with correct facts. Since you are genuinely interested in Biology there are lots of High School level Biology books, maybe reading one might help you.

Answer: Phenotype is what you observe (Ex.: visually or with a blood test) , genotype is what your genetic material provides the plans for: a guide to protein synthesis and maybe subsequent metabolic processes to allow your body to display the phenotype. Maybe. So yes, you can give someone a new eye with a different eye color. You did NOT change any genes that create eye color. Why? the new eye was created inside another mother and had genes to create another color. Human eyes do not regrow, unfortunately.

Also, IMO, it is beyond extremely unlikely that you could successfully transplant an entire eye and get it wired up to work correctly given the state of modern Science. If we assume you can do that, then what we create with an eye transplant may be possibly considered a chimera. What's that? Did you ever see healthy plants that have blotchy leaves - like deep green and yellow - on the same leaf? That is a chimera. The bush has two different sets of genetic material in one organism. The one I have in mind is the result of a virus infection that persists from plant->seed->new plant.

Human-animal chimeras created in the lab - have been studied - this is a workshop announcement, note the ethical component:
http://osp.od.nih.gov/office-biotechnology-activities/event/2015-11-06-133000-2015-11-06-220000/workshop-research-animals-containing-human-cells.

Fraternal twins that fuse at a very early stage can create humans that are normal, but with two genotypes, not one:
https://en.wikipedia.org/wiki/Chimera_(genetics)#Humans

Another issue is gene expression or what is called incomplete (or partial) penetrance. Sometimes the organism has the genotype for a trait but does not "display" it. This was an explanation up until recently for odd eye colors. In a sense it is still correct, I guess.

Anyway, your blue-brown idea of eye color needs a serious tuneup:
https://en.wikipedia.org/wiki/Eye_color
More layman friendly:
http://sandwalk.blogspot.com/2007/02/genetics-of-eye-color.html

 

[Docscientist]

@jim mcnamara
Please answer to the point.What do you think would be the result of such an eye transplantation ? And please do be more precise about what is my misconception in this particular topic.

 

[jim mcnamara]

I did answer your point - nothing will happen.
1. because right now it is completely impossible - therefore speculation, more correctly nobody knows for sure.
2. genotype only has a big effect on eye development when you are an embryo.
3. Medicines like travatan can change your eye color.
4. eye color is not as fixed or immutable as you seem to think.

I gave you a classification of the resulting person - a chimera. Transplants with functioning kidneys require immunosuppression - turning off the immune system in the person with the new kidney, so that the new kidney is not killed by the immune system of the person who got it.

Without using examples what are you trying to ask? What happens when an adult gets a donor organ - in terms of genetics? Answer: not much.
If the organ survives, usually the patient survives as well. Which is good. The only other option is the chimera thing - where the immune system has two sets of DNA from the very start. This is from fraternal twin embryos merging, most commonly.

 

[Docscientist]

2. genotype only has a big effect on eye development when you are an embryo.

That is the answer to the point.

 

[Evo]

Say a girl has brown eyes .she meets with an accident which causes her to undergo an eye transplantation.The donor has blue eyes and the girl gets them.Now does she possesses a blue or brown eye ? So she genetically has brown eyes but phenotypically has blue eyes ? Is it like that? But phenotype is controlled by genotype,isn't it ?

Do you have any actual resources where an eye transplant was done, or are you just making this up?

I do not find any whole eye transplants. I see iris (colored portion) transplants as very dangerous and not successful and only for cosmetic effects
Cosmetic Iris Implants Carry Risk of Permanent Eye Damage, Vision Loss
http://www.mirror.co.uk/news/techno...orrifying-footage-shows-damage-caused-5070481

You have been warned before about this. Thread closed.