Sunday, April 1, 2012

Eyes


"The iris is the colored portion of the eye surrounding the pupil. Like fingerprints, iris patterns are highly complex and uniquely identify individuals. Examples of iris characteristics include crypts, which are oval-shaped areas within the iris; pigmented rings that surround the pupil; furrow contractions, which are radial and concentric bands around the pupil; and pigmented spots on the iris, also called nevi. (For illustrations of these patterns, see our blog post.) The heritability of various types of iris patterns ranges between 70-95%, meaning that genetics contribute strongly to these traits."


Andrea Campbell's eyes


rs1533995 AG typical appearance of crypts in eye - this is the flowery shape around the edges
rs3739070  AA typical appearance of iris furrow contractions - which are circular and radial bands that result from the iris folding in exactly the same location each time
rs12896399 TT Slightly less pronounced or absent pigmentation rings around the pupil, on average, which means there is no yellow to make her eye appear green, thus it appears blue


In Europeans, 72% chance of blue eyes; 27% chance of green eyes; 1% chance of brown eyes.
 GG Three studies have found that blue eyes most often result if a person has two copies of the G version of this OCA2-controlling SNP, suggesting that the genetic origin of the trait can be traced back to a single point in human evolution.
Andrea Campbell

My eyes:
rs1533995 AA Slightly more pronounced crypts (flowery shapes around edge), on average
rs3739070 AA typical appearance of iris furrow contractions - which are circular and radial bands that result from the iris folding in exactly the same location each time
rs12896399 GT Typical degree of  (yellow) pigmentation rings around the pupil

rs1393350 CG (like my mom)
Typical odds of having blue instead of green eyes, if eyes are non-brown.


my eyes are blue, with yellow flecks



"A study of people from Iceland and the Netherlands found that variations in a gene involved in melanin production affect a person’s odds of having green as opposed to blue eyes. Assuming a person already has non-brown eyes, the study found that each A at rs1393350 increases the odds of having blue rather than green eyes about 1.4 times."

rs12896399 GT (unlike my mom)

Typical odds of having blue instead of green eyes, if eyes are non-brown.

A study of people from Iceland and the Netherlands found that, assuming a person already has non-brown eyes, each T at rs12896399 increases the odds of having blue rather than green eyes about 1.5 times.


The arrows mark examples of crypts. A. No crypts. E. Many large crypts. The American Journal of Human Genetics 89, 334–343, August 12, 2011.
The arrow marks a pigmented ring around the pupil. A. Absence of pigmented ring. B. Yellow/green ring on a blue iris. The American Journal of Human Genetics 89, 334–343, August 12, 2011.




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