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Is this pedigree explanation correct?


denisepr

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Hello everyone, I'm new here so I apologize if this was already posted... also for the long post and for any mistake in the writing (english is not my first language)

So I have a pedigree (see attachment) and I know it is X linked recessive but I'm not sure if my explanation is adequate so please correct me if I'm wrong or if my explanation doesn't make sense. Also if you want to add something I will appreciate it. If you don't want to read my explanation and just want to give me yours proceed to *** those are the two questions I'm trying to explain.

I know it is recessive because this mutation manifests in one parental and in some individuals in the third and fourth generation but it does not manifest in the second generation. The male parental has the mutation but the female parental does not so that will mean the female progeny (2nd generation) will be carriers and the male progeny will be normal. With this information I know the female parental is dominant homocygous because none of their progeny express the mutation, they are carriers (if she was heterocygous there will be at least one male or female with the mutation).

 

The mutation will manifest in the third generation depending with who their parents mate. If in the second generation, a heterocygous female mates with a normal male their progeny will at least have one male with the mutation, one normal male, one heterocygous female and one homocygous female.

 

If the male from the third generation who has the mutation mates with an heterocygous female then their progeny (4th generation) will be one male with the mutation, one male without the mutation, one female heterocygous and one female with the mutation (homocygous for the recessive allele).

 

Evidence for recessive: I.2 is mutant but II.2, II.3, II.4, II.6 doesn't have the mutation but are carriers

Evidence for X linked: I.2, III.5, III.10, IV.4, IV.6, IV.8 are mutants and have recessive alleles

 

Does this explains why the pedigree is x linked recessive?

 

***How do I know the mutation is dominant or recessive?

***How do I know if the mutation is X linked or somatic?

***provide evidence for each case

 

If someone can explain to me why is not somatic I will truly appreciate it, I know its not but I don't know how to explain it correctly and I don't know if my explanation above is enough.

 

Again sorry for the long post or any bad writing and thanks for your help :)

 

 

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