4. Mother and daughter with unusual eye color patterns
Eye color is inherited gene. This mother and her daughter are a perfect example of that. Their resemblance is quite clear. They share the same beautiful eyes. One eye is dark brown and the other is blue. The scientific term is heterochromia iridium. The difference in coloration is caused by lack of the melanin pigment.
Heterochromia of the eye is of three kinds. In complete heterochromia, one iris is a different color from the other. In sectoral heterochromia, part of one iris is a different color from its remainder and finally in “central heterochromia” there are spikes of different colours radiating from the pupil.
Eye color, specifically the color of the irises, is determined primarily by the concentration and distribution of melanin. The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). In humans, usually, an excess of melanin indicates hyperplasia of the iris tissues, whereas a lack of melanin indicates hypoplasia.
(courtesy of en.wikipedia.org)