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The polymorphisms may be in an OCA2 regulatory sequence, where they may influence the expression of the gene product, which in turn affects pigmentation. [13] A specific mutation within the HERC2 gene, a gene that regulates OCA2 expression, is partly responsible for blue eyes. [9] Other genes implicated in eye color variation are SLC24A4 [22 ...
Eye color is an example of a (physical) phenotypic trait. A phenotypic trait, [1] [2] simply trait, or character state [3] [4] is a distinct variant of a phenotypic characteristic of an organism; it may be either inherited or determined environmentally, but typically occurs as a combination of the two. [5]
Simple heterochromia – a rare condition characterized by the absence of other ocular or systemic problems. The lighter eye is typically regarded as the affected eye as it usually shows iris hypoplasia. It may affect an iris completely or only partially. Congenital Horner's syndrome [16] – sometimes inherited, although usually acquired.
Optogenetics also necessarily includes the development of genetic targeting strategies such as cell-specific promoters or other customized conditionally-active viruses, to deliver the light-sensitive probes to specific populations of neurons in the brain of living animals (e.g. worms, fruit flies, mice, rats, and monkeys).
The most common form is caused by a genetic condition called congenital red–green color blindness (including protan and deutan types), which affects up to 1 in 12 males (8%) and 1 in 200 females (0.5%) [3]. The condition is more prevalent in males, because the opsin genes responsible are located on the X chromosome. [2]
The reason boils down to genes. A senior lecturer in biomolecular sciences at Liverpool John Moores University said, "What we know now is that eye color is based on 12 to 13 individual variations ...
The genes also play a role in the development and stability of the retina by influencing the structure and function of both the rod photoreceptor cells and supporting cells called the retinal pigmented epithelium. Mutations that affect the normal function of these genes can result in retinitis pigmentosa and resultant vision loss. [citation needed]
The four pigments in a bird's cone cells (in this example, estrildid finches) extend the range of color vision into the ultraviolet. [1]Tetrachromacy (from Greek tetra, meaning "four" and chroma, meaning "color") is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye.