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Blue eyes are a highly sexually dimorphic eye color. Studies from various populations in Europe have shown that men are substantially more likely to have blue eyes than women. [18] The inheritance pattern followed by blue eyes was previously assumed to be a Mendelian recessive trait, though this has been
Reddish eyes are due to the lack of pigment in the iris pigment epithelium. When the stroma is unpigmented but the iris pigment epithelium is not, mammalian eyes appear blue. Melanin in the pigment epithelium is critical for visual acuity and contrast. [4] Loss of melanogenesis function is linked to the gene that encodes tyrosinase.
A null allele is a gene variant that lacks the gene's normal function because it either is not expressed, or the expressed protein is inactive. For example, at the gene locus for the ABO blood type carbohydrate antigens in humans, [13] classical genetics recognizes three alleles, I A, I B, and i, which determine compatibility of blood transfusions.
According to the model of Mendelian inheritance, alleles may be dominant or recessive, one allele is inherited from each parent, and only those who inherit a recessive allele from each parent exhibit the recessive phenotype. Offspring with either one or two copies of the dominant allele will display the dominant phenotype.
Ojos Azules (Spanish: [ˈoxos aθˈules], 'Blue Eyes') was a breed of shorthaired [1] [2] domestic cat with unusual blue or odd eyes [1] caused by a dominant blue eye (DBE) genetic mutation. The breed came in all coat colors; however, only particolors ( bicolors and tricolors ), colorpoints , and intermediate colors with a characteristic white ...
Albinism results from inheritance of recessive gene alleles and is known to affect all vertebrates, including humans. It is due to absence or defect of tyrosinase , a copper-containing enzyme involved in the production of melanin .
Oculocutaneous albinism is a form of albinism involving the eyes , the skin (-cutaneous), and the hair. [1] Overall, an estimated 1 in 20,000 people worldwide are born with oculocutaneous albinism. [1] OCA is caused by mutations in several genes that control the synthesis of melanin within the melanocytes. [2]
In the example on the right, both parents are heterozygous, with a genotype of Bb. The offspring can inherit a dominant allele from each parent, making them homozygous with a genotype of BB. The offspring can inherit a dominant allele from one parent and a recessive allele from the other parent, making them heterozygous with a genotype of Bb.