![]() They claimed that whenever both parents had blue eyes, all of the children have blue eyes, but their data actually included two hazel-eyed offspring of blue-eyed parents. Family studiesÄavenport and Davenport (1907) were the first to suggest that blue eye color was caused by a recessive allele. Some people have a blue or green iris with a brown ring around the pupil (Sturm and Larsson 2009), which makes the classification of eye color even more complicated. Eye color can change dramatically in the first few years of life, as many babies are born with blue eyes but then develop green or brown eyes (Matheny and Dolan 1975), and changes can also occur later in life (Bito et al. 2011) or the hue and saturation values quantified (Liu et al. This has been criticized as an oversimplification (Brues 1975), and eye colors have been divided into nine categories (Mackey et al. Many studies divide eye colors into three categories: blue (or blue and gray) green and hazel and brown. Blue, gray, green and hazel eyes are only common in people of European ancestry other people's eyes are various shades of brown. Irises with little melanin appear blue due to scattering of light by collagen fibers in the iris. The color of the iris is determined by the amount of melanin, the ratio of eumelanin (which is dark brown) to pheomelanin (which is reddish), and the way the melanin is distributed in the eye. Many people who know nothing else about genetics think that two blue-eyed parents cannot have a brown-eyed child. One of the oldest myths in human genetics is that having blue eyes is determined by a single gene, with the allele for blue eyes recessive to the allele for non-blue eyes (green, brown, or hazel).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |