Posted: Nov 08, 2017 3:39 pm
The answer is in that first Wikipedia paragraph you quoted - it's an autosomal recessive condition. Individuals only manifest the condition if both copies of the mutant gene are inherited.
Let D represent the normal 5α-reductase gene, and d represent the defective version of the gene. individuals inherit two genes, one from the mother, one from the father.
If the individual inherits a D from his mother, and a D from his father, his genotype is DD, and he is unaffected by the condition.
If the individual inherits a D from his mother, and a d from his father, his genotype is Dd, and he is likewise unaffected by the condition. The working D gene is dominant, and preferentially expressed, therefore he produces a working version of the enzyme, and the DHT pathway operates as normal.
If the individual inherits a D from his mother, and a d from his father, his genotype is dD, and he is likewise unaffected by the condition. The working D gene is dominant, and preferentially expressed, therefore he produces a working version of the enzyme, and the DHT pathway operates as normal.
If the individual inherits a d from his mother, and a d from his father, his genotype is dd, and he is affected by the condition. None of his copies of the 5α-reductase gene are working, so the DHT pathway is not triggered as normal.
Let D represent the normal 5α-reductase gene, and d represent the defective version of the gene. individuals inherit two genes, one from the mother, one from the father.
If the individual inherits a D from his mother, and a D from his father, his genotype is DD, and he is unaffected by the condition.
If the individual inherits a D from his mother, and a d from his father, his genotype is Dd, and he is likewise unaffected by the condition. The working D gene is dominant, and preferentially expressed, therefore he produces a working version of the enzyme, and the DHT pathway operates as normal.
If the individual inherits a D from his mother, and a d from his father, his genotype is dD, and he is likewise unaffected by the condition. The working D gene is dominant, and preferentially expressed, therefore he produces a working version of the enzyme, and the DHT pathway operates as normal.
If the individual inherits a d from his mother, and a d from his father, his genotype is dd, and he is affected by the condition. None of his copies of the 5α-reductase gene are working, so the DHT pathway is not triggered as normal.