On isolating a new strain of mutant mice, prelimiminary matings suggest the new mutant phenotype isn't inherited autosomally. How can it be determined if the mutant phenotype is X-linked dominant...

On isolating a new strain of mutant mice, prelimiminary matings suggest the new mutant phenotype isn't inherited autosomally. How can it be determined if the mutant phenotype is X-linked dominant or has a mitochondrial type inheritance pattern.

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justaguide | College Teacher | (Level 2) Distinguished Educator

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The mutation in the mice is not inherited autosomally, i.e. the probability of males as well as females inheriting the genes that cause the mutation from their parents is not the same.

It has to be determined if the mutant phenotype is X-linked dominant or a has a mitochondrial inheritance pattern.

A X-linked dominant mutant phenotype is transmitted by a father with the specified phenotype to all of his daughters, not to his sons. On the other hand an affected mother has a 50% probability of passing it on to all her children both sons all well as daughters. If the mutation has a mitochondrial type inheritance pattern, all the children of a female with the mutant phenotype will inherit it. A father cannot pass on the mutation to his children.

To determine the inheritance pattern of the mutant phenotype, a male mouse affected by it should have children with a female mouse that does not have the mutation. The resulting offspring should be tested and if it is found that all the female offspring are affected, it is a X-linked dominant mutant phenotype. If that is not the case, an affected female with the mutant phenotype should have children with a normal male. If all the offspring born are affected, the mutant phenotype has mitochondrial inheritance pattern.

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