Pedigree Q6


Explanation: the last one was a bit more tricky. Although one family had all affected people, the next generation did not have any at all. So, although you might think “dominant” to start, you know that with one affected parent, there is a 50% chance for each offspring to have the disease. Here the low probability of getting 0 affected out of 6 children should make you think again. That second look could make you realise that autosomal recessive fits better. Therefore, the mother of the indicated person is mutant/mutant and there is 100% likelihood the child will be a carrier. Have a look again to check: link (new tab).

on we go.

The family indicated by the arrow are expecting another child; what is the likelihood that that child will develop the genetic condition?