Which of the following types of genetic illness will not be passed on from a father to his male offspring?
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Here we have to understand that when a girl child is born, she inherits an X-chromosome from the mother and another X-chromosome from the father. A boy child on the other hand inherits the Y-chromosome from the father and the X-chromosome from the mother.
If the father is a carrier of an X-linked dominant illness, the son will not be affected as he receives the X-chromosome only from the mother. On the other hand the daughter is sure to be afflicted with the ailment.
For any X-linked dominant ailment to affect a boy child it has to be passed on through the X-chromosome that he receives from the mother.
X-linked recessive genetic ailments are also not passed on from the father to the male offspring.
For all the other types of genetic ailments either the father is not involved or the chances of the father contributing to passing on the illness are the same for both the male and the female offspring.
Therefore X-linked dominant and X-linked recessive genetic illnesses cannot be passed on from the father to his male offspring.
Autosomal dominant and recessive are mutations that occur on any chromosome, not just the X and Y sex chromosomes. Autosomal dominant genetic illnesses just need one copy of the defective gene to be afflicted. There are no carriers of autosomal dominant diseases.
Autosomal recessive requires two copies of the defect to affect the individual. Persons with one copy of the defective gene typically do not suffer the effects of the defect but are carriers, meaning they can pass on the defective gene to their offspring. Males and female offspring are affected equally by autosomal defects.
X-linked genetic disorders occur on the X sex gene. Males (XY) pass on their Y chromosome to their sons and their X chromosomes to their daughters. Once again dominant means only one copy of the genetic defect is needed to affect the individual, making the daughter of an affected male affected as well. X-linked recessive requires two copies of the defective chromosome, making the daughter of an affected male a carrier unless she inherits the same X-linked defect from her mother's X chromosome. Because males do not pass on X-linked chromosomes to their sons, this type of genetic illness (X-linked recessive and dominant) cannot be passed on to male offspring.
Because a male parent only passes on their Y chromosome to their male offspring, a defect of a y-linked chromosome would result in an affected male offspring.
While males have mitochondrial DNA, only female pass that DNA onto their offspring. A male with a genetic disorder linked to mitochondrial DNA would not pass the disorder onto his male child because he does not pass on any mitochondrial DNA to his offspring.
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