Mitochondrial inheritance, also known as maternal inheritance, applies to genes in mitochondrial DNA. Both alleles influence the genetic trait or determine the characteristics of the genetic condition.ДЄBOВ blood group, alpha-1 antitrypsin deficiency In codominant inheritance, two different versions (alleles) of a gene are expressed, and each version makes a slightly different protein. Y chromosome infertility, some cases of Swyer syndrome Because only males have a Y chromosome, in Y-linked inheritance, a variant can only be passed from father to son. Glucose-6-phosphate-dehydrogenase-deficiency, X-linked thrombocytopeniaДЄ condition is considered Y-linked if the altered gene that causes the disorder is located on the Y chromosome, one of the two sex chromosomes in each of a male's cells. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons (no male-to-male transmission). In females (who have two X chromosomes), one altered copy of the gene usually leads to less severe health problems than those in affected males, or it may cause no signs or symptoms at all. In males (who have only one X chromosome), an alteration in the only copy of the gene in each cell is sufficient to cause the condition. X-linked disorders are caused by variants in genes on the X chromosome, one of the A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons (no male-to-male transmission).Д«ecause the inheritance pattern of many X-linked disorders is not clearly dominant or recessive, some experts suggest that conditions be considered X-linked rather than X-linked dominant or X-linked recessive. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. In females (who have two X chromosomes), a variant would have to occur in both copies of the gene to cause the disorder.

In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. X-linked recessive disorders are also caused by variants in genes on the X chromosome. Females may experience less severe symptoms of the disorder than males. In females (who have two X chromosomes), a variant in one of the two copies of the gene in each cell is sufficient to cause the disorder. X-linked dominant disorders are caused by variants in genes on the X chromosome.В In males (who have only one X chromosome), a variant in the only copy of the gene in each cell causes the disorder. Autosomal recessive disorders are typically not seen in every generation of an affected family. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition. In autosomal recessive inheritance, variants occur in both copies of the gene in each cell. In others, the condition may result from a new variant in the gene and occur in people with no history of the disorder in their family. In some cases, an affected person inherits the condition from an affected parent. One altered copy of the gene in each cell is sufficient for a person to be affected by an autosomal dominant disorder. These conditions are usually inherited in one of several patterns, depending on the gene involved: Some genetic conditions are caused by variants (also known as mutations) in a single gene.

Are dominant traits more common