Biology - Inheritance of X-linked dominant characteristics
Inheritance of X-linked dominant characteristics
X-linked indicates that the allele  is on the X-chromosome and
therefore linked to the sex of the individual. For example, XRXR, XRXr or
XRY or XrY. Which individuals would express (show) the characteristic?
* All daughters of affected fathers will show the characteristic (if the
father is affected he has one X chromosome with the defective allele; this
would be passed on to the daughter)
* An affected son must have an affected mother (a son has one X
chromosome from his mother; if he has the characteristic then the mother
must have been affected)
* More females than males are likely to show the characteristic.
Examples of genetic disorders following the X-linked dominant pattern of
* weakness and wasting of the muscles of the legs and hands
* vitamin-D resistance for rickets
* There are only a few X-linked dominant disorders. Can you suggest why?
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