02-28-2017, 09:22 PM
(This post was last modified: 02-28-2017, 10:20 PM by SunilNagpal.)
![[Image: 6931eb92a4b04caf864f8031fc9dba2d.jpg]](https://uploads.tapatalk-cdn.com/20170228/6931eb92a4b04caf864f8031fc9dba2d.jpg)
(Right now in a train going back to my home town
![](https://emoji.tapatalk-cdn.com/emoji4.png)
To me option B seems the right answer (it can either be an X linked recessive one or only Y linked). Both cases hold good for the given pedigree.
Only Y linked is evidently very much applicable in the entire scenario and hence this is definitely there. Now the problem I see is that most of you are overlooking the fact that the mothers can be non-carriers as well.
xx - Xy (where X is the carrier chromosome) is very much possible in entire pedigree and if the disease is X linked recessive, females will not be affected in the given pedigree.
Edit:
Correcting myself: Non-carrier mother is not applicable here as sons in the progeny are affected. A carrier mother with an affected father, can always give birth to a carrier daughter (as one should look at the births as isolated events).